Methods and apparatus for controlled placement of a polymer composition into a web

ABSTRACT

The present invention relates to methods for the controlled placement of a curable, shear thinnable polymer composition into a porous web. The controlled placement is performed by applying tension to the porous web. The polymer composition is applied onto a surface of the web. The composition is shear thinned sufficiently to reduce its viscosity and selectively place it into the tensioned web to encapsulate at least some of the structural elements of the web, leaving most of the interstitial spaces of the porous web open. The invention also relates to methods for selectively placing the polymer composition in a substantially continuous region extending through the web so that the polymer composition fills the interstitial spaces and adheres adjacent structural elements in the region. In the areas in the web above and below the filled region, at least some of the structural elements are encapsulated and most of the interstitial spaces are open. The invention also relates to methods for the controlled placement of a polymer composition into a tensioned porous substrate having a matrix of open cells by applying a localized shear force to selectively distribute a curable, shear thinnable polymer composition within the substrate, at least partially individually lining the cell walls of at least some of the cells, and leaving most of the cells open.

CROSS-REFERENCE TO RELATED PATENT APPLICATIONS

This application is a continuation-in-part of U.S. patent applicationSer. No. 08/017,855 filed on Feb. 16, 1993 now U.S. Pat. No. 5,418,051,which is a continuation of my earlier filed U.S. patent application Ser.No. 07/680,645, filed Apr. 2, 1991 now U.S. Pat. No. 5,209,965 which isa continuation of U.S. patent application Ser. No. 07/319,778, filedMar. 10, 1989 now U.S. Pat. No. 5,004,643 which was a continuation inpart of U.S. patent application Ser. Nos. 167,630; 167,643; 167,797; and167,869, all now abandoned, all filed on Mar. 14, 1988 and allincorporated herein by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to methods of and apparatus for theintroduction of sufficient energy to controllably and selectively placea polymer composition into a porous web. The present invention moreparticularly relates to methods of and apparatus for the controlledplacement of a curable, shear thinning, polymer composition into a web.The controlled placement is preferably performed through the energycontrolled viscosity and rheology modified placement of the polymercontrolled manner by 1) applying the polymer composition onto a surfaceof a web, 2) shear thinning the composition and placing it into the web,and 3) curing the polymer composition. This method and apparatusproduces a web that either has some of its fibers or structural elementsencapsulated by the polymer composition while at least some of theinterstitial spaces of the web are open; or has an internal layerextending through the web in a direction generally spaced from at leastone major surface thereof; or has both encapsulated structural elementsand an internal layer of polymer composition.

2. Description of Related Art

In the prior art, it has been proposed to treat porous webs, especiallyfabrics, with silicone resins and also with fluorochemicals.Conventional treatments of webs fall into the general categories of (i)surface coatings and (ii) saturations or impregnations.

For example, U.S. Pat. Nos. 3,436,366; 3,639,155; 4,472,470; 4,500,584;and 4,666,765 disclose silicone coated fabrics. Silicone coatings areknown to exhibit relative inertness to extreme temperatures of both heatand cold and to be relatively resistant to ozone and ultraviolet light.Also, a silicone coating can selectively exhibit strength enhancement,flame retardancy and/or resistance to soiling. Fluorochemical treatmentof webs is known to impart properties, such as soil resistance, greaseresistance, and the like.

Prior art fluorochemical and silicone fabric treatment evidently canprotect only that side of the fabric upon which they are disposed. Suchtreatments significantly alter the hand, or tactile feel, of the treatedside. Prior silicone fabric coatings typically degrade the tactilefinish, or hand, of the fabric and give the coated fabric side arubberized finish which is not appealing for many fabric uses,particularly garments.

U.S. Pat. No. 4,454,191 describes a waterproof and moisture-conductingfabric coated with a hydrophilic polymer. The polymer is a compressedfoam of an acrylic resin modified with polyvinyl chloride orpolyurethane and serves as a sort of "sponge", soaking up excessmoisture vapor. Other microporous polymeric coatings have been used inprior art attempts to make a garment breathable, yet waterproof.

Various polyorganosiloxane compositions are taught in the prior art thatcan be used for making coatings that impart water-repellency to fabrics.Typical of such teachings is the process described in U.S. Pat. No.4,370,365 which describes a water repellent agent comprising, inaddition to an organohydrogenpolysiloxane, either one or a combinationof linear organopolysiloxanes containing alkene groups, and a resinousorganopolysiloxane containing tetrafunctional and monofunctionalsiloxane units. The resultant mixture is catalyzed for curing anddispersed into an aqueous emulsion. The fabric is dipped in the emulsionand heated. The resultant product is said to have a good "hand" and topossess waterproofness.

This type of treatment for rendering fabrics water repellent withoutaffecting their "feel" is common and well known in the art. However, ithas not been shown that polyorganosiloxanes have been coated on fabricsin such a way that both high levels of resistance to water by thefibers/filaments and high levels of permeability to water vapor areachieved. As used herein, the term "high levels of permeability to watervapor" has reference to a value of at least about 500 gms/m² l/day, asmeasured by ASTM E96-80B. Also, as used herein, the term "high level ofwaterproofness" is defined by selective testing methodologies discussedlater in this specification. These methodologies particularly deal withwater resistance of fabrics and their component fibers.

Porous webs have been further shown to be surface coated in, forexample, U.S. Pat. Nos. 4,478,895; 4,112,179; 4,297,265; 2,893,962;4,504,549; 3,360,394; 4,293,611; 4,472,470; and 4,666,765. These surfacecoatings impart various characteristics to the surface of a web, but donot substantially impregnate the web fibers. Such coatings remain on thesurface and do not provide a film over the individual internal fibersand/or yarn bundles of the web. In addition, such coatings on the websurface tend to wash away quickly.

Prior art treatments of webs by saturation or impregnation also sufferfrom limitations. Saturation, such as accomplished by padbath immersion,or the like, is capable of producing variable concentrations of a givensaturant chemical.

To treat a flexible web, by heavy saturation or impregnation with apolymer material, such as a silicone resin, the prior art has suggestedimmersion of the flexible web, or fabric, in a padbath, or the like,using a low viscosity liquid silicone resin so that the low viscosityliquid can flow readily into, and be adsorbed or absorbed therewithin.The silicone resin treated product is typically a rubberized web, orfabric, that is very heavily impregnated with silicone. Such a treatedweb is substantially devoid of its original tactile and visualproperties, and instead has the characteristic rubbery properties of acured silicone polymer.

U.S. Pat. No. 2,673,823 teaches impregnating a polymer into theinterstices of a fabric and thus fully filling the interstices. Thispatent provides no control of the saturation of the fabric. It teachesfull saturation of the interstices of the fabric.

The prior art application of liquid or paste compositions to textilesfor purposes of saturation and/or impregnation is typically accomplishedby an immersion process. Particularly for flexible webs, includingfabric, an immersion application of a liquid or paste composition to theweb is achieved, for example, by the so-called padding process wherein afabric material is passed first through a bath and subsequently throughsqueeze rollers in the process sometimes called single-dip, single-nippadding. Alternatively, for example, the fabric can be passed betweensqueeze rollers, the bottom one of which carries the liquid or pastecomposition in a process sometimes called double-dip or double-nippadding.

Prior art treatment of webs that force a composition into the spaces ofthe web while maintaining some breathability have relied on using lowviscosity compositions or solvents to aid in the flow of thecomposition. U.S. Pat. No. 3,594,213 describes a process forimpregnating or coating fabrics with liquified compositions to create abreathable fabric. This patent imparts no energy into the composition toliquify it while forcing it into the spaces of the web. The compositionis substantially liquified before placement onto and into the web. U.S.Pat. No. 4,588,614 teaches a method for incorporating an active agentinto a porous substrate. This patent utilizes a solvent to aid in theincorporation of the active agent into the web.

Prior art apparatus for the coating of webs, including fabrics,generally deposits a coating onto the fabric at a desired thickness.Coating at a predetermined thickness can be achieved by deposition ofcoating material or by the scraping of a coating upon the fabric byknives. Flexible webs are generally urged between oppositely disposedsurfaces, one of which would be a doctoring blade or drag knife. Theblade or knife smooth the coating and maintain the thickness of thecoating to a desired thickness. For example, it is possible to apply arelatively thick silicone liquid elastomer coating to a rough web,typically of fiberglass, in order to make architectural fabric as istaught in U.S. Pat. No. 4,666,765. In this example, the drag knives areset to a thickness of about 2 to 10 mils thicker than the web thickness.This setting, depending on the coating speed, can yield a base coatthickness of approximately 3 to 12 mils thicker than the web thickness.

Various types of coatings, and various coating thicknesses, arepossible. However, a general principle of coating machinery is that thecoating material is swept, or dragged, along the surface of the fabric.No special attention is normally given to any pressured forcing of thecoating into the fabric, therein making the coating also serve as animpregnant. Of course, some coating will be urged into surface regionsof the fabric by the coating process. Generally, however, application ofhigh transversely exerted (against a fiber or web surface) forces at thelocation of the coating deposition and/or smoothing is not desired inthe prior art processes because it is the goal of the prior art coatingprocesses to leave a definite thickness of coating material upon asurface of the fabric, and not to scrape the fabric clean ofsurface-located coating material.

One prior art silicone resin composition is taught by U.S. Pat. Nos.4,472,470 and 4,500,584, and includes a vinyl terminated polysiloxane,typically one having a viscosity of up to about 2,000,000 centipoises at25° C., and a resinous organosiloxane polymer. The composition furtherincludes a platinum catalyst, and an organohydrogenpolysiloxanecrosslinking agent, and is typically liquid. Such composition is curableat temperatures ranging from room temperature to 100° C. or higherdepending upon such variables as the amount of platinum catalyst presentin the composition, and the time and the temperature allowed for curing.

Such compositions may additionally include fillers, including finelydivided inorganic fillers. Silicone resin compositions that are free ofany fillers are generally transparent or translucent, whereas siliconeresin compositions containing fillers are translucent or opaquedepending upon the particular filler employed. Cured silicone resincompositions are variously more resinous, or hard, dependent upon suchvariables as the ratio of resinous copolymer to vinyl terminatedpolysiloxane, the viscosity of the polysiloxane, and the like.

Curing (including polymerization and controlled crosslinking) canencompass the same reactions. However, in the fabric finishing arts,such terms can be used to identify different phenomena. Thus,controllable and controlled curing, which is taught by the prior art,may not be the same as control of crosslinking. In the fabric finishingarts, curing is a process by which resins or plastics are set in or ontextile materials, usually by heating. Controlled crosslinking may beconsidered to be a separate chemical reaction from curing in the fabricfinishing arts. Controlled crosslinking can occur between substancesthat are already cured. Controlled crosslinking can stabilize fibers,such as cellulosic fibers through chemical reaction with certaincompounds applied thereto. Controlled crosslinking can improvemechanical factors such as wrinkle performance and can significantlyimprove and control the hand and drape of the web. Polymerization canrefer to polymer formation or polymer growth.

SUMMARY OF THE INVENTION

The present invention includes methods and apparatus for controlling aporous web under tension, for applying a curable or semi-curable, shearthinnable polymer composition onto the surface of the web, for shearthinning the polymer composition, and placing it into the web toposition the polymer within the web in a certain manner, and forpartially or fully curing the polymer composition. The methods andapparatus of this invention control the placement of the compositioninto the web to either encapsulate the structural elements (i.e., thefibers or filaments) making up the web leaving at least some of theinterstitial spaces open or providing an internal layer of polymerbetween the upper and lower surfaces of the web, or some combination ofthe foregoing.

The methods and apparatus of the present invention permits theapplication of the polymeric composition onto the surface of the web bya variety of means. After the polymer is applied to the surface of theweb, the polymer composition is preferrably immediately shear thinned tocontrollably and significantly reduce its viscosity and place it intoselected places within the web. To aid in this process, the web ispreferably distorted, typically by stretching at the location of theshear thinning. This distortion facilitates the entrance of the polymercomposition into the web by creating a double or dual shear thinning. Inthe case of the web, this is produced by the combination of the edgecondition of the blade, the engineered shear thinnable polymer, thespeed of the web, and the subsequent repositioning of the fibers andfilaments after their immediate passage under the edge of the blade.

Controlled placement of the polymer composition within a web may beperformed by a basic embodiment of a machine in accordance with thepresent invention, that is as simple as an applicator to apply viscouspolymer to the surface of the web, a pair of facilities for applyingtension to a section of the web and a blade forced against the web inthe section under tension. The web is pulled under tension past theblade, or, alternatively, the blade is moved relative to the web, andthe forces generated by the blade cause the polymer composition to flowinto the three-dimensional matrix of the web, and controllably beextracted out of the web leaving a thin film of polymer encapsulatingselected fibers, or an internal layer of polymer, or both. Tension onthe web is preferably released thereafter, and the web is cured.

The present invention includes novel methods and apparatus formanufacturing webs, fibers and fabrics that have certain desirablephysical qualities such as water resistance, increased durability, andimproved barrier qualities by combining the use of encapsulated fibersand filaments and a breathable or controlled pore size internal coatingwith a controlled surface chemistry modification and the like. Suchwebs, fibers and fabrics can be used to prepare a wide variety ofproducts including, but not limited to, carpets, specialized clothing,career apparel, bioengineered surfaces for diagnostic applications, andupholstery. By use of the present invention, webs, fibers and fabricscan be manufactured with a wide variety of desired physicalcharacteristics.

Methods and apparatus of the present invention can treat webs or fabricswhich are generally flat or planar with great internal precision of theinternal placement, by combining the use of encapsulated fibers andfilaments and a breathable or controlled pore size internal layer, witha controlled surface chemistry modification. Surface chemistry iscontrolled by using sufficient web tension and frontal blade energy todislodge the fluorochemical from the web which is then caused to surfaceorient and/or bloom. The webs or fabrics can comprise fibers in the formof monofilaments, yarns, staples, or the like. The webs or fabrics canalso be comprised of a matrix having open cells or pores therein. Thewebs or fabrics may be a fabric which is woven or non-woven with fibersthat can be of any desired composition. The webs or fabrics willgenerally be tensionable, but not too weak or elastomeric to beprocessed in accordance with the teachings of the present invention. Anyweb that is too weak or elastomeric can be treated in accordance withthe subject invention if it is laminated to a support backing of paper,film, such as Mylar, or the like and controllably stretched or notstretched prior to applying the backing, thereby setting the conditionunder which it is stabilized so that it can be treated in accordancewith this invention.

The methods and apparatus of this invention are also applicable totreating discrete sheets or pieces of webs such as papers, film sheets,foam sheets, leather hides, woven and non-woven sheets, and the like.The sheet is fed into the apparatus and stops. It is placed undertension and polymer is applied. Rigid or non-rigid blades are movedacross the surface of the sheet--to cause the controlled placement ofthe polymer within the sheet as previously described. A non-rigid bladecan be flexible but must have sufficient shearing capability.

Webs treated by the methods and apparatus of the present inventioncontain a curable or semi-curable polymer or copolymer that may containmonomers that are present as a film, coating, or layer within a web thatenvelopes or encapsulates at least a portion of the fibers or cell orpore walls of the web. The internal layer is a region generally spacedfrom the outer surfaces of the web which is substantially continuouslyfilled by the combination of the polymers controllably placed thereinand the fibers and filaments of the web in this region. The intersticesor open cells in the region of the internal layer are also substantiallyfilled. The outer surfaces of the web are substantially free of anypolymer deposits other than the thin film encapsulation of the surfacefibers and filaments. However, the web remains breathable and is eitherwater resistant or waterproof. The thickness of the internal layer isgenerally in the range of 0.01 to 50 microns.

At a microscopic level, a web treated in accordance with the presentinvention, for example, a fabric, can be regarded as being a complexstructure, but generally the internal layer is discernable undermicroscopic examination as shown in the accompanying scanning electronmicroscope photographs that will be discussed hereinafter.

Depending upon the conditions used to produce it, a web produced inaccordance with the present invention can characteristically andpreferably exhibit a soft hand and flexibility that is comparable to thehand and flexibility of the untreated web. In some cases, the differencebetween the hand and the feel of the treated and untreated webs may notbe perceptible, but may be engineered to be altered through thecontrolled crosslinking of the polymer. This is particularly surprisingin view of the substantial amount of polymer being added to the web. Atreated web has a breathability which, by a present preference, canapproach a high percentage of the untreated web notwithstanding therelatively large amount of polymer present.

A polymer composition having a viscosity in the range of greater than1,000 centepoise but less than 2,000,000 centepoise is preferably usedto produce the treated webs. If desired, additives or modifiers can beadmixed with such a composition to adjust and improve properties of suchcomposition or web, such as viscosity and/or rheology, combustibility,reflectivity, flexibility, conductivity, light fastness, mildewresistance, rot resistance, stain resistance, grease resistance, and thelike. In general, a web treated in accordance with this inventionexhibits enhanced durability. These additives are generally controlledby the engineered shear thinning polymer composition and the method andapparatus of this invention to be oriented and surface exposed on thesurface of the thin film on the encapsulated fibers, or on one or bothsurfaces of the internal layer, or on one or both surfaces of the web,or some combination of the above.

A web made by the present invention can preserve much, or evensubstantially all, of its original untreated hand even after an extendedperiod of use while demonstrating excellent abrasion resistance. Incontrast, an untreated web typically loses its original hand anddisplays reduced abrasion resistance after an extended period of use.This is achieved by the formation of an internal layer that prevents newfiber surfaces from being exposed, thereby minimizing the amount ofuntreated surfaces that degrade much faster than the treated fibers.

A web treated by this invention can undergo a large number of machinewashings with detergent without experiencing appreciable or significantchange or deterioration. The polymer matrix composition prolongs the useand service life of a web, usually by at least an order of magnitude,depending on such factors as web type, extent and type of treatment bythe teachings of this invention, and the like.

Optionally, and as indicated above, agents or additives carried by thepolymer composition into a web can be stably fixed and selectivelyplaced in the web with the cured polymer. For example, agents such asultraviolet light absorbers, dulling agents, reflectivity enhancers,antimicrobial agents, flame resistant agents, heat absorbant,anti-static agents, and the like, which modify a web's response to lightand radiation are desirably located substantially upon the surfaces ofthe web's fibers. When these agents are incorporated into the envelopingpolymer film, it appears that they are retained where they aredeposited. A present preference for ultraviolet resistant webs in thepractice of this invention is to employ a silicone polymer compositionthat contains a benzophenone.

In addition, the present invention is directed to methods and apparatusfor making polymer encapsulated and internally coated webs. Such methodsand apparatus includes means for tensioning a porous, flexible web;means for applying a curable, shear thinnable, polymer compositionthereto; and means for applying a localized shear force sufficient tocause the controlled shear thinning of an engineered polymer over andagainst one or both surfaces of the tensioned web. The shear force issufficient to shear thin the polymer, to selectively distribute andplace the polymer composition within the web as an internal layer in aregion extending generally in spaced relationship to the surfaces of theweb and to generally envelop surface portions of at least some of theweb fibers or form a lining of the cells or pores of the web. Theinternal layer is not necessarily flat but may undulate or meanderthrough the web, occasionally even touching one or both surfaces of theweb. Alternatively, the shear force and other variables are controlledto encapsulate at least some of the internal and external fibers of theweb without forming an internal layer. Also, control of the methods andapparatus can result in a treated web having a combination of aninternal layer and encapsulation of at least some of the fibers of theweb leaving at least some of the interstitial spaces open. The web isthen optionally interveningly stored, or is (preferably) immediatelysubjected to curing conditions (heat, moisture and/or radiation) whichconverts the polymer composition as deposited in the web into a solidelastomeric polymer. The web can be semi-cured or partially cured andcan be finally cured or post cured at a later time.

Various other and further features, embodiments, and the like which areassociated with the present invention will become apparent and betterunderstood to those skilled in the art from the present descriptionconsidered in conjunction with the accompanying drawings whereinpresently preferred embodiments of the invention are illustrated by wayof example. It is to be expressly understood, however, that the drawingsand the associated accompanying portions of this specification areprovided for purposes of illustration and description only, and are notintended as limitations on the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a graphical plot illustrating the flow of a silicone polymercomposition over time upon and in fabrics both pretreated and untreatedwith water repellent chemicals, such as fluorochemicals.

FIG. 2 is a plan view of a prior art silicone polymer treated fabricmagnified 150 times.

FIG. 3a is a photomicrograph of a fabric of the invention magnified 120times.

FIG. 3b is a cross section of a fiber bundle fabric of FIG. 3a magnified600 times.

FIG. 3c is a view of the side of the fabric of FIG. 3a that is theopposite of the side to which silicone polymer was applied.

FIGS. 4a and 4b illustrate diagrammatically one embodiment of a methodand apparatus suitable for use in the practice of the present invention.

FIG. 5 is a diagrammatic representation illustrating the process inaccordance with the present invention.

FIG. 6 illustrates diagrammatically another embodiment of a methods andapparatus suitable for use in the practice of the present invention.

FIG. 7 illustrates diagrammatically another embodiment of a method andapparatus suitable for use in the practice of the present invention.

FIGS. 8a through 8d are graphs illustrating ways of plotting rheologicalbehavior.

FIG. 9 is a schematic vector diagram illustrating surface tensionforces.

FIG. 10 is a graph relating contact angle over a smooth, solid surface.

FIGS. 11a, 11b, 11c and 11d show representative velocity profiles.

FIGS. 12a, 12b and 12c illustrate diagrammatically other methods andapparatus suitable for use in the practice of the present invention.

FIGS. 13a, 13b and 13c are scanning electron microscope photomicrographsof another representative fabric made in accordance with of the presentinvention.

FIG. 14 illustrates diagrammatically another and presently preferredembodiment of methods and apparatus suitable for use in the practice ofthe present invention.

FIGS. 15a, 15b, 15c, 15d, 15e, 15f, 15g, 15h and 15i are scanningelectron microscopy (SEM) photomicrographs and elemental analyses whichdepict various results in fabrics, fibers and filaments from backscatter evaluation tests.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

The following description is of the best presently contemplated mode ofcarrying out the invention. This description is made for the purpose ofillustrating the general principles of the inventions and should not betaken in a limiting sense.

The present invention relates to methods and apparatus for manufacturinga treated web. The subject methods and apparatus involve the control ofnumerous variables, including, without limitation, web tension (bothoverall web tension as well as the web tension immediately before andafter each individual blade), angle of entry of web into each blade,blade angle in relation to horizonal reference point, blade pressureagainst moving web, angle of exit of web from each blade, web speed,number of blades, the pressure of the leading nip rolls, the pressure ofthe trailing nip rolls, static control, thickness of each blade, bevelon each blade, oven cure temperature, oven cure dwell time, bladetemperature and blade surfaces and edge conditions and blade finish.

Other variables that affect the finished product, but are not directlyrelated to the methods and apparatus, include, without limitation, thepolymer blend, the starting viscosity of the polymer composition,accelerators added to the polymer composition, additives added to thepolymer composition, the type of web used, ambient temperature,humidity, airborne contaminants, lint on web, pre-treatment of web,sub-web surface temperature, and web moisture content.

With respect to the blades, the temperature of the blade can be keptcool to keep the polymer composition from curing prematurely. This canbe accomplished by passing a coolant through or around the blade or byother means well known in the art. Alternatively, the blade could beheated by passing a heated fluid around or through the blade, if desiredto improve or alter the viscosity and rheology for the required changesin the polymer necessary to achieve a specific product.

The blade finish is also important. A hard, smooth surface of both bladeface and edges is desirable to shear thin the polymer and keep itflowing and to maximize friction or selectively create shear forcesbetween the web, the polymer, and blade(s). For some applications, theblades should preferably remain rigid in all dimensions and have minimalresonance in order to get uniform web treatment.

The apparatus has facilities for rotating the angle of each blade ±90°from the vertical. In order to vary the shear and placement forces ofthe blade against the web, polymer and additives, adjustment facilitiesare provided for moving the blade vertically up and down and moving theblade forward and backward horizontally. All three axis are importantfor creating the desired control which causes the encapsulated fibersand/or filaments, the additive placement and orientation on the fiberand filaments, the optional internal layer, and the controlled thicknessof the encapsulating films or internal layer. The lateral placement ofeach blade relative to the other is also important and facilities areprovided for allowing lateral movement of each blade toward and awayfrom each other. The lateral placement of each blade controls the microtension and elastic vibration of the web between the preceding roll andthe blade, thereby controlling the web after the immediate exit of theweb from the blade and controlling the Coanda Effect, as described inU.S. Pat. No. 4,539,930, so that controlled placement of the internallayer takes place.

Changing the tension of the web results in changes internally in theweb, such as the position of the internal layer of the web, as well ashow much or how little fiber encapsulation occurs, and the thickness ofthe film encapsulating the individual fibers or filaments.

At the leading edge of the blade, the web is stretched longitudinallyand the polymer is simultaneously and dynamically shear thinned, placedinto the web, and partially extracted from the web, thereby leavingencapsulated fibers and filaments and/or an internal layer. As the webpasses the leading edge of the blade, the elastic recovery forces of theweb combined with the relaxation or elastic recovery of the fibers andfilaments causes fiber encapsulation and the surface chemistrymodification (or bloom). It is believed that this occurs by the poppingapart of the individual fibers and filaments. The fibers and filamentseither pull the polymer from the interstitial spaces or the rheology ofthe polymer attracts it to the fibers and filaments or some combinationof the two. The end result is that the polymer in the interstitialspaces moves to the fibers and filaments as they move or snap apart,thereby creating encapsulated fibers and filaments. At the bottomsurface of the blade, the thickness, depth, and controlled placement ofthe internal layer is determined. A wider blade results in a thickerinternal layer of polymer. Further, the dynamics of stretch andrelaxation of the fibers provides for an even energy necessary for thethin film encapsulation of the polymer composition over the fibers.

Passing the treated web through the exit nip rolls pushes the fibers orstructural elements of the web together. The hardness of and thematerial of the exit nip rolls affects the finished web. The exit niprolls could be either two rubber rolls or two steel rolls, or one steelroll and one rubber roll, and the rubber rolls could be of differentdurometers. Further, the variation of the hardness of one or both niprolls changes the contact area or footprint between the nip rolls andthe web as the web passes therebetween. With a softer roll there is alarger contact area and the web is capable of retaining the (a) thinfilm encapsulation of the individual fibers and filaments, (b) thecontrolled placement of the internal coating, and (c) controlledplacement of the additives in (a) and (b). With a harder roll there is asmaller contact area which is appropriate for heavier webs.

Additional controllable variables include the various controls of eachblade, the nip rolls durometer, the nip release effect, the nip surfacecharacteristics, the guidance, and the pre-treatment of the substrate.Some of the controllable variables are: 1) web tension, 2) angle ofentry of fabric into the blade, 3) blade angle in reference tohorizontal position, 4) blade pressure against fabric (blade height), 5)angle of exit of fabric from blade, 6) web speed, 7) number of blades,8) initial rheology and viscosity of polymers, 9) nip pressure, 10)entry nip pressure 11) static control, 12) blade thickness and shape,13) polymers and polymer blends, 14) accelerators and inhibitors addedto polymers, 15) additives in polymers, 16) oven cure temperature, 17)oven cure dwell time, 18) substrate type, 19) ambient polymertemperature, 20) humidity, 21) degree web is deformed under lateraltension, and 22) airborne contaminants and lint on the web. Control ofthe above variables affects: (a) the thin film encapsulation of theindividual fibers and filaments, (b) the controlled placement of theinternal coating, and (c) the controlled placement of the additives in(a) and (b).

An increase in web tension causes less polymer to be applied to the web,and also, more of what is applied to be extracted from the web. Webtension occurs between the entrance pull stand and the exit pull stand.The primary tension is a result of the differential rate between thedriven entrance pull stand and the driven exit pull stand whereby theexit pull stand is driven at a rate faster than the entrance pull stand.Other factors which effect tension are (1) the blade roll diameter, (2)the vertical depth of the blade(s), (3) the durometer of the entrancepull stand roll and rubber roll of the exit pull stand, and (4) thefriction as the web passes under the blade(s). The larger the blade rolldiameter, the higher the tension of the web. If the drive rate of theweb remains constant, then increasing the depth of the blade into theweb creates a greater micro tension condition under the blade.Similarly, decreasing the depth into the web decreases the micro tensionunder the blade. The lower the durometer of the entrance pull stand rolland rubber roll of the exit pull stand, the larger the footprint orcontact area between the rolls. A larger footprint produces more surfacefriction, thereby limiting web slippage and increasing tension.Likewise, web slippage can be effected by changing the surface textureof the rolls, i.e., a smooth roll will allow greater slippage than ahighly contrasting or rough surface texture. Increasing friction, as thefabric passes under the blade(s), also produces tension. Friction is afunction of the surface area of the bottom of the blade(s). Increasingthe surface area increases the friction which increases the tension.

The entry angle of the web into the blade(s) can be varied by blade rollheight, blade roll diameter, blade angle, distance between prior bladeroll(s) and blade(s), and height of the blades. Increasing the bladeroll height and blade roll diameter increases the entry angle into theblade. Rotating the blade angle clockwise from the perpendicular, withthe web running left to right, increases the entry angle. Likewise,rotating the blade angle counter-clockwise from the perpendicular, withthe web running left to right, decreases the entry angle. Decreasing thedistance between the roll before the blade and the blade decreases theangle of entry. Increasing the downward depth of the blade(s) into theweb decreases the angle of entry into the blade(s).

The angle of the blade(s) is completely changeable and fully rotationalto 360°. The fully rotational axis provides an opportunity for more thanone blade per rotational axis. Therefore, a second blade having adifferent thickness, bevel, shape, resonance, texture, or material canbe mounted. Ideally the apparatus contains two or three blades per blademount.

The blade height or blade pressure applied against a web can be obtainedthrough the vertical positioning of the blade(s) in the blade mount. Thegreater the downward depth of the blade(s), the greater the pressure.Blade pressure against the web is also accomplished through the tensionof the web as described above.

The same line components that affect the entry angle of the web into theblade(s), also affect the exit angle of the web out of the blade. Anychanges in blade roll(s) vertical height, diameter, or distance awayfrom the blade, affects the exit angle of the web. If the angle of theblade is rotated clockwise as described above, the entry angle of theweb increases, thus decreasing the exit angle.

Web speed is proportional to the variable speed of the motor whichdrives the entrance and exit nip stands. Web speed can effect thephysics of the polymers as the web passes under the blades.

The number of blades can vary. Generally, more than one blade isrequired. The polymer is first applied onto the web prior to the firstblade. At this blade, a rolling bead of polymer can exist at theinterface of the blade and the web (entry angle) Basically, a highviscosity polymer is applied and through the process of shear thinning,the viscosity is greatly decreased, allowing the polymer to enter intothe interstitial spaces of the web. Any blade(s) after the first blade,serves to further control the polymer rheology and viscosity andcontinue the controlled placement of the polymer into the web. This isaccomplished by controllably removing excess polymer to obtain an evendistribution of polymer to any area, or a combination of the three areasof a) the thin film encapsulation of the individual fibers andfilaments, b) the controlled placement of the internal layer, and c) thecontrolled placement of the additives in a) and b).

The initial process dynamics for the rheology and viscosity of thepolymer is designed and engineered with the required attributes toachieve (a) the thin film encapsulation of the individual fibers andfilaments, (b) the controlled placement of the internal layer, and (c)the controlled placement of the additives in (a) and (b). If the polymerviscosity is high, the polymer may need to be pre-thinned by using adynamic mixer or three-roll head, as shown in FIG. 12a. The dynamicmixer or the three-roll head can significantly reduce the viscosity andeven pre-place the polymer into a thick substrate or web to allow theblades to further shear thin and enhance the flow and placement of thepolymer.

The entrance pull stand is a driven roll proportionally driven at apredetermined rate slower than the exit pull stand. The entrance andexit pull stands are adjustable from about 100 pounds of force to 5 ormore tons of force.

The bottom rolls of both the entrance and exit pull stands havemicro-positioning capability to provide for gap adjustment andalignment. The composition of the top roll of the entrance and exit pullstands is chosen based on the durometer of the urethane or rubber. Thetop roll of the exit pull stand preferably utilizes a Teflon sleevewhich will not react with the polymers used in the process. The bottomroll of the exit pull stand is preferably chrome plated or highlypolished steel to reduce the impression into the preplaced polymer inthe web.

If desired, non-contact antistatic devices may be installed in locationswhere noticeable levels of static buildup are detected. However, thereis no evidence of adverse effects due to static buildup in the process.

Blade thickness and shape have substantial effects on the movement ofthe structural elements of the web during processing and moreimportantly, the viscoelastic flow characteristics of the polymer incontrolling (a) the thin film encapsulation of the individual fibers andfilaments, (b) the controlled placement of the internal coating, and (c)the controlled placement of the additives in (a) and (b). The bladebevel can effect the entry angle of the web and effect the sharpness ofthe leading edge of the blade. A sharper leading edge has a greaterability to push the weave or structural elements of the weblongitudinally and traversely, increasing the size of the interstitialspaces. As the web passes the leading edge of the blade, theinterstitial spaces snap back or contract to their original size. Thepolymer viscosity is reduced and the polymer is placed into the web atthe leading edge of the blade. Blade thickness and shape effects thepolymers and their selected additives and the placement thereof.Preferably, the combination of the leading edge condition and the twosurfaces (the front and the bottom) that meet at the leading edge areRMS 8 or better in grind and/or polish. This creates a precise leadingedge; the more precise the leading edge, the more the shear thinningcontrol.

There are a number of pre-qualifiers or engineered attributes ofpolymers that enhance control of flow and polymer placement in:(a) thethin film encapsulation of the individual fibers and filaments, (b) thecontrolled placement of the internal coating, and (c) the controlledplacement of the additives in (a) and (b). Blending polymers is one wayto achieve ideal flow and placement characteristics. An example of ablended polymer is where one polymer, selected for its physicalproperties, is mixed with another polymer that is selected for itsviscosity altering properties. Many tests using different polymer blendshave been done. Polymer blends vary by both chemical and physicaladhesion, durability, cure dwell time required, cure temperaturerequired, flexibility, percentage add-on required, performancerequirements, and aesthetics.

Accelerators and inhibitors which are added to polymers, generallyproduce three effects. An illustrative accelerator or inhibitor is aplatinum catalyst, which is a cure or crosslinking enhancer. The firsteffect it produces is to control the time and temperature of the web asit cures. A cure or controlled crosslinking enhancer can significantlyassist in controlling the drape and hand feel of the web. The secondeffect is to to alter the cure to allow the web to reach partial cureand continue curing after leaving an initial heat zone. This secondeffect also assists in retaining the drape and hand feel of the web. Thethird effect of inhibitors is to achieve a semi-cure for later stagingof the cure.

Additives which are added to the polymers significantly control surfacechemistry. Surface chemistry characteristics are controlled by includingadditives that have both reactive and bio-interactive capabilities. Themethod and apparatus of this invention can control the placement of theadditives on the surface of the thin film encapsulating the fibers, oneither or both surfaces of the internal layer, on either or bothsurfaces of the web, or any combination of the foregoing.

The oven cure temperature and the source and type of cure energy, arecontrolled for a number of reasons. The oven cure temperature iscontrolled to achieve the desired crosslinked state; either partial orfull. The source and type of energy can also affect the placement of thepolymer and additives. For example, by using a high degree of specificinfrared and some convection heat energy for cure, some additives can bestaged to migrate and/or bloom to the polymer surfaces.

Oven cure temperature is thermostatically controlled to a predeterminedtemperature for the web and polymers used. Machine runs of new webs arefirst tested with hand pulls to determine adhesion, cure temperature,potentials of performance values, drapability, aesthetics, etc. Theeffect on the web depends on the oven temperature, dwell time and curingrate of the polymer. Webs may expand slightly from the heat.

Oven cure dwell time is the duration of the web in the oven. Oven curedwell time is determined by the speed of the oven's conveyor andphysical length of the oven. If the dwell time and temperature for aparticular web is at maximum, then the oven conveyor speed would dictatethe speed of the entire process line or the length of the oven wouldhave to be extended in order to increase the dwell time to assure properfinal curing of the web.

The physical construction and chemistry of the web is critical. Theamount of control over the rheology of the polymer and the tension onthe web are dependent on the physical construction and chemistry. Theweb selected must have physical characteristics that are compatible withthe flow characteristics of the polymer.

The ambient polymer temperature refers to the starting or first stagingpoint to controlling the viscosity and rheology. The process head cancontrol the ambient polymer temperature through temperature controlledpolymer delivery and controlled blade temperatures.

Humidity can sometimes inhibit or accelerate curing of the polymer.Therefore, humidity needs to be monitored and, in some conditions,controlled.

The degree the web is deformed under lateral tension is controllable bythe choice of the physical construct of the web, the blade angle, theblade leading edge condition, and the micro and macro tension of theweb.

Airborne contaminants and lint on the web can affect primability and cancreate pin holes in the polymer. Therefore, airborne contaminants andlint on the web need to be controlled to reduce or eliminate pin holesor uncontrolled primability.

In view of the fact that between the shear thinning stations and theoven, the polymer composition may begin to set or partially cure, it maybe desirable to overshear so that by the time the web gets to the curingoven, it will be at the point where it is desired that the cure occur.This over shear effect is a matter of controlling certain variables,including the force of the blades against the moving web, as well as thetension and speed of the web.

By having a number of shear thinning blades, you create a multiple shearthinning effect, which changes the final construct of the polymer andthe (a) thin film encapsulation of the individual fibers and filaments,(b) controlled placement of the internal coating, and (c) controlledplacement of the additives in (a) and (b). It is understood that thefirst shear thinning causes viscoelastic deformation of the polymercomposition which, due to its memory, tends to return to a certainlevel. With each multiple shear thinning, the level to which the polymerstarts at that shear point and returns is changed. This is calledthixotropic looping or plateauing.

Definitions

The term "web" as used herein is intended to include fabrics and refersto a sheet-like structure (woven or non-woven) comprised of fibers orstructural elements. Included with the fibers can be non-fibrouselements, such as particulate fillers, binders, dyes, sizes and the likein amounts that do not substantially affect the porosity or flexibilityof the web. While preferably, at least 50 weight percent of a webtreated in accordance with the present invention is fibers, morepreferred webs have at least about 85 weight percent of their structureas fiber. It is presently preferred that webs be untreated with anysizing agent, coating, or the like, except as taught herein. The web maycomprise a laminated film or fabric and a woven or non-woven poroussubstrate. The web may also be a composite film or a film laminated to aporous substrate or a double layer.

The term "webs" includes flexible and non-flexible porous webs. Websusable in the practice of this invention can be classified into twogeneral types:

(A) Fibrous webs; and

(B) Substrates having open cells or pores, such as foams.

A porous, flexible fibrous web is comprised of a plurality of associatedor interengaged fibers or structural elements having interstices orintersticial spaces defined therebetween. Preferred fibrous webs caninclude woven or non-woven fabrics. Other substrates include, but arenot limited to, a matrix having open cells or pores therein such asfoams or synthetic leathers.

The term "fiber", as used herein, refers to a long, pliable, cohesive,natural or man-made (synthetic) threadlike object, such as amonofilament, staple, filament, or the like. A fiber usable in thisinvention preferably has a length at least 100 times its diameter orwidth. Fibers can be regarded as being in the form of units which can beformed by known techniques into yarns or the like. Fibers can be formedby known techniques into woven or non-woven webs (especially fabrics)including weaving, knitting, braiding, felting, twisting, matting,needling, pressing, and the like. Preferably, fibers, such as those usedfor spinning, as into a yarn, or the like, have a length of at leastabout 5 millimeters. Fibers such as those derived from cellulosics ofthe type produced in paper manufacture can be used in combination withlonger fibers as above indicated, as those skilled in the art willreadily appreciate.

The term "filament" as used herein refers to a fiber of indefinitelength.

The term "yarn" as used herein refers to a continuous strand comprisedof a multiplicity of fibers, filaments, or the like in a bundled form,such as may be suitable for knitting, weaving or otherwise used to forma fabric. Yarn can be made from a number of fibers that are twistedtogether (spun yarn) or a number of filaments that are laid togetherwithout twist (a zero-twist yarn).

A flexible porous web used as a starting material in the presentinvention is generally and typically, essentially planar or flat and hasgenerally opposed, parallel facing surfaces. Such a web is athree-dimensional structure comprised of a plurality of fibers withinterstices therebetween or a matrix having open cells or pores therein.The matrix can be comprised of polymeric solids including fibrous andnon-fibrous elements.

Non-fibrous elements, such as particulate fillers, binders, dyes, sizesand the like can be added to fibers in a web. Preferred webs have atleast about 85% of their structure comprised of fibrous or fibermaterials and are untreated with any sizing agent, coating, or the like.

Two principal classes of substrates having open pores or cells may beutilized in the present invention: leathers (including natural leathers,and man-made or synthetic leathers), and foamed plastic sheets (orfilms) having open cells.

Foamed plastic sheet or film substrates are produced either bycompounding a foaming agent additive with resin or by injecting air or avolatile fluid into the still liquid polymer while it is being processedinto a sheet or film. A foamed substrate has an internal structurecharacterized by a network of gas spaces, or cells, that make suchfoamed substrate less dense than the solid polymer. The foamed sheets orfilm substrates used as starting materials in the practice of thisinvention are flexible, open-celled structures.

Natural leathers suitable for use in this invention are typically splithides. Synthetic leathers have wide variations in composition (orstructure) and properties, but they look like leather in the goods inwhich they are used. For purposes of technological description,synthetic leathers can be divided into two general categories: coatedfabrics and poromerics.

Synthetic leathers which are poromerics are manufactured so as toresemble leather closely in breathability and moisture vaporpermeability, as well as in workability, machinability, and otherproperties. The barrier and permeability properties normally areobtained by manufacturing a controlled microporous (open celled)structure.

Synthetic leathers which are coated fabrics, like poromerics, have abalance of physical properties and economic considerations. Usually thecoating is either vinyl or urethane. Vinyl coatings can be either solidor expanded vinyl which has internal air bubbles which are usually aclosed-cell type of foam. Because such structures usually have anon-porous exterior or front surface or face, such structures displaypoor breathability and moisture vapor transmission. However, since theinterior or back surface or face is porous, such a coated fabric can beused in the practice of this invention by applying the polymer to theback face.

The fibers utilized in a porous flexible web treated by the methods andapparatus of the present invention can be of natural or syntheticorigin. Mixtures of natural fibers and synthetic fibers can also beused. Examples of natural fibers include cotton, wool, silk, jute,linen, and the like. Examples of synthetic fibers include rayon,acetate, polyesters (including polyethyleneterephthalate), polyamides(including nylon), acrylics, olefins, aramids, azlons, glasses,modacrylics, novoloids, nytrils, rayons, sarans, spandex, vinal, vinyon,regenerated cellulose, cellulose acetates, and the like. Blends ofnatural and synthetic fibers can also be used.

With respect to the fluorochemical liquid dispersions (or solutions)which can optionally be used for web pretreatment, the term"impregnation" refers to the penetration of such dispersions into aporous web, and to the distribution of such dispersions in a preferably,substantially uniform and controlled manner in such web, particularly asregards the surface portions of the individual web component structuralelements and fibers.

With respect to the polymer compositions used in this invention, theterm "controlled placement" or "placement" refers to the penetration ofsuch polymer compositions into a porous web, to the distribution of suchcomposition in a controlled manner through such web, and to theresultant, at least partial envelopment of at least a portion of thefibers of such web by such composition in accordance with the presentinvention, or to the formation of an internal layer, or both.

The word "thixotropy" refers herein to liquid flow behavior in which theviscosity of a liquid is reduced by shear agitation or stirring. It istheorized to be caused by the breakdown of some loosely knit structurein the starting liquid that is built up during a period of rest(storage) and that is torn down during a period of suitable appliedstress.

The term "coating" as used herein, refers to a generally continuous filmor layer formed by a material over or on a surface.

The term "internal coating or internal layer" as used herein, refers toa region spaced from the outer surfaces of the web which issubstantially continuously filled by the combination of the polymercontrollably placed therein and the fibers and filaments of the web inthe specified region. Such coating or layer envelopes, and/or surrounds,and/or encapsulates individual fibers, or lines cell or pore walls ofthe porous web or substrate, in the specified region. The internal layeris not necessarily flat but may undulate or meander through the web,occasionally even touching one or both surfaces of the web.

The term "envelop" or "encapsulate" as used interchangeably herein,refers to the partial or complete surrounding, encasement, or enclosingby a discrete layer, film, coating, or the like, of exposed surfaceportions of at least some individual fiber or lining of a cell or porewall of a porous web. Such a layer can sometimes be contiguous orintegral with other portions of the same enveloping material whichbecomes deposited on internal areas of a web which are adjacent to suchenveloping layer, enveloped fiber, lined cell or pore wall, or the like.

The term "elastomeric" as used herein refers to the ability of a curedpolymer treated web to stretch and return to its original state.

The term "curing", or "cure", as used herein, refers to a change instate, condition, and/or structure in a material, such as a curablepolymer composition that is usually, but not necessarily, induced by atleast one applied variable, such as time, temperature, radiation,presence and quantity in such material of a curing catalyst or curingaccelerator, or the like. The term "curing" or "cured" covers partial aswell as complete curing. In the occurrence of curing in any case, suchas the curing of such a polymer composition that has been selectivelyplaced into a porous flexible substrate or web, the components of such acomposition may experience occurrence of one or more of complete orpartial (a) polymerization, (b) cross-linking, or (c) other reaction,depending upon the nature of the composition being cured, applicationvariables, and presumably other factors. It is to be understood that thepresent invention includes polymers that are not cured after applicationor are only partially cured after application.

The term "filled" as used herein in relation to interstices, orintersticial spaces, or open cells, and to the amount of polymercomposition therein in a given web, substrate, or the fibers in such webor substrate, designates the presence of such composition therein. Whena given intersticial space or open cell is totally taken up by suchcomposition, it is "completely filled" or "plugged". The term "filled"also refers to an intersticial space having a film or layer of polymercomposition over or through it so that it is closed even though theentire thickness of the interstitial space is not completely filled orplugged.

Measurements of the degree of envelopment, interstitial fillage,plugging, or the like in an internal coating are conveniently made bymicroscopy, or preferably by conventional scanning electron microscopy(SEM) techniques. Because of the nature of such measuring by SEM forpurposes of the present invention, "a completely filled" interstitialspace or open cell can be regarded as a "plugged" interstitial space oropen cell.

The term "polymer", or "polymeric" as used herein, refers to monomersand oligomers as well as polymers and polymeric compositions, andmixtures thereof, to the extent that such compositions and mixtures arecurable and shear thinnable.

The term "shear thinning", in its broadest sense, means the lowering ofthe viscosity of a material by the application of energy thereto.

A porous web or fabric is preferably untreated or scoured before beingtreated in accordance with the present invention. Preferably a web canbe preliminarily treated, preferably saturated, for example, by padding,to substantially uniformly impregnate the web with a fluorochemical.Typically, and preferably, the treating composition comprises adispersion of fluorochemical in a liquid carrier. The liquid carrier ispreferably aqueous and can be driven off with heat after application.The treating composition has a low viscosity, typically comparable tothe viscosity of water or less.

After such a treatment, it is presently preferred that the resultingtreated web exhibits a contact angle with water measured on an outersurface of the treated web that is greater than about 90 degrees. Thetreated web preferably contains fluorochemical substantially uniformlydistributed therethrough. Thus, the fluorochemical is believed to belocated primarily on and in the individual fibers, cells or pores withthe web interstices or open cells being substantially free offluorochemical.

A presently preferred concentration of fluorochemical in a treatmentcomposition is typically in the range of about 1 to about 10%fluorochemical by weight of the total treating composition weight, andmore preferably is about 2.5% of an aqueous treating dispersion. Webweight add-ons of the fluorochemical can vary depending upon suchfactors as the particular web treated, the polymer composition to beutilized in the next step of the treatment process of this invention,the ultimate intended use and properties of the treated web of thisinvention, and the like. The fluorochemical weight add-on is typicallyin the range of about 0.01 to about 5% of the weight of the untreatedweb. After fluorochemical controlled placement, the web is preferablysqueezed to remove excess fluorochemical composition after which the webis heated or otherwise dried to evaporate carrier liquid and therebyalso accomplish fluorochemical insolubilization or sintering, ifpermitted or possible with the particular composition used.

The fluorochemical treated web thereafter has a predetermined amount ofa curable polymer composition controllably placed within the web by themethods and apparatus of this invention, to form a web whose fibers,cells or pores are at least partially enveloped or lined with thecurable polymer composition, whose web outer surfaces are substantiallyfree of the curable polymer, whose web interstices or open cells are notcompletely filled with the curable polymer and which may also contain aninternal layer of polymer. The curable polymer composition utilizedpreferably exhibits a viscosity greater than 1,000 centipoise and lessthan 2,000,000 centipoise at rest at 25° C. at a shear rate of 10reciprocal seconds.

The fluorochemical residue that remains after web treatment may not beexactly evenly distributed throughout the web, but may be present in theweb in certain discontinuities. For example, these discontinuities maybe randomly distributed in small areas upon an individual fiber'ssurface. However, the quantity and distribution of fluorochemicalthrough a web is believed to be largely controllable. Some portions ofthe fluorochemical may become dislodged from the web and migrate throughthe polymer due to the forces incurred by the shear thinning andcontrolled placement of the polymer.

The curable polymer composition is believed to be typically polymeric,(usually a mixture of co-curable polymers and oligomers), and to includea catalyst to promote the cure. The polymers that can be used in thepresent invention may be monomers or partially polymerized polymerscommonly known as oligomers, or completely polymerized polymers. Thepolymer may be curable, partially curable or not curable depending uponthe desired physical characteristics of the final product. The polymercomposition can include conventional additives.

While silicone is a preferred composition, other polymer compositionscan include, polyurethanes, fluorosilicones, silicone-modifiedpolyurethanes, acrylics, polytetrafluoroethylene-containing materials,and the like, either alone or in combination with silicones.

It is to be understood that the depth of polymer placement into a webcan be controlled by the methods and apparatus herein described toprovide selective placement of the polymer within the substrate or web.The web is thereafter optionally cured to convert the curablecomposition into a solid elastomeric polymer.

The polymer composition is theorized to be caused to flow and distributeitself over fibers, cells or pores in a web under the influence of theprocessing conditions and apparatus provided by this invention. Thisflow and distribution is further theorized to be facilitated andpromoted by the presence of a fluorochemical which has beenpreliminarily impregnated into a web, as taught herein. The amount offluorochemical or fluorochemical residue in a web is believed toinfluence the amount, and the locations, where the polymer will collectand deposit, and produce encapsulated fibers and/or an internal layer inthe web. However, there is no intent to be bound herein by theory.

Some portion of the residue of fluorochemical resulting from apreliminary web saturating operation is theorized to be present upon atreated fiber's surfaces after envelopment of fibers, cells or pores bythe polymer has been achieved during the formation of the encapsulatingfiber and/or the internal layer by the practice of this invention. Thisis believed to be demonstrated by the fact that a web treated by thisinvention still exhibits an enhanced water and oil repellency, such asis typical of fluorochemicals in porous webs. It is therefore believedthat the fluorochemicals are affecting the adherence of the polymer as athin film enveloping layer about the treated fibers, cells or pores aswell as facilitating polymer pressurized flow within and about theinterstices or open cells of the web being treated so that the polymercan assume its position enveloping the fibers or lining the cells orpores of the substrate.

In those fabrics that are pretreated with fluorochemicals, the exactinterrelationship between the polymer film and the impregnatedfluorochemical is presently difficult, or perhaps impossible, toquantify because of the variables involved and because transparentpolymer is difficult to observe by optical microscopy. It can betheorized that perhaps the polymer and the fluorochemical each tend toproduce discontinuous films upon the fiber surface, and that such filmsare discontinuous in a complementary manner. It may alternatively betheorized that perhaps the polymer film is contiguous, or substantiallyso, relative to fluorochemical molecules on a fiber surface, and thatthe layer of polymer on a fiber surface is so thin that any dislodgementof the fluorochemical may release the fluorochemical into the polymerfilm thereby allowing the fluorine to orient or project through the filmwith the required cure temperature of the polymer, reactivating thewater surface contact angle so that the water repellent properties ofthe fluorochemical affect the finished product. However, regardless ofphysical or chemical explanation, the combination of polymer film andfluorochemical results in a fiber envelopment or cell or pore walllining and the formation of encapsulated fibers and/or an internal layerof polymer in a web when this invention is practiced. After curing, thepolymer is permanently fixed material.

By using the methods and apparatus of this invention, one can achieve acontrolled placement of a polymer composition into a porous substrate orweb to obtain a desired treated web.

A curable polymer such as used in the practice of this invention isapplied under pressure using shear forces onto and into a web orsubstrate. The shear forces cause the curable silicone polymer to flowinto the web. The extent of fiber envelopment and cell or pore walllining is believed to be regulatable by controlling such factors asdiscussed previously, as well as the selection and applied amount offluorochemical, if any, the curable polymer used, and the appliedcompressive and shear forces employed at a given temperature so thatfiber envelopment is achieved while the interstices and/or open cells ofthe web are not completely filled with such polymer in the region of theinternal layer, and the outer opposed surfaces of the web aresubstantially completely free of polymer coating or residue. After sucha procedure, the curable polymer is then cured.

The curable polymer is applied onto the surface of the web. Then, theweb, while tensioned, is passed over and against shearing means orthrough a compression zone, such as between rollers or against a shearknife. Thus, transversely applied shear force and compressive pressureis applied to the web. The combination of tension, shearing forces, andweb speed is sufficient to cause the polymer to move into the web andout from the interstices or open cells around the web fibers, cells, orpores being enveloped. The result is that at least some of theinterstices and/or open cells are unfilled in regions of the web outsideof the region occupied by the internal coating or internal layer, andare preferably substantially free of polymer. Excess polymer is removedby the surface wiping action of the shearing means. The curable polymerenveloping the fibers is thereafter cured.

The desired penetration of, and distribution and placement of polymerin, a web is believed to be achieved by localized pressuring forcesexerted on a web surface which are sufficiently high to cause theviscosity of a polymer composition to be locally reduced, therebypermitting such polymer to flow under such pressuring and to becontrollably placed within the web and to envelope its fibers or linethe cell or pore walls thereof. To aid in this process, the web ispreferably at least slightly distorted by tensioning or stretching,while being somewhat transversely compressed at the location of thecontrolled placement. This distortion is believed to facilitate theentrance of the polymer composition into the web. When the compressionand tension are released, the polymer composition is believed to besqueezed or compressed within and through the interstitial spaces, oropen cell spaces, of the treated web.

If, for example, too much polymer is present in the finished product,then either or both the tension and shear force can be increased, andvice versa for too little polymer. If flow is not adequate upon thefibers, producing incomplete fiber envelopment, then the viscosity ofthe polymer composition can be reduced by increasing the pressures andtemperatures employed for the controlled placement thereof.Alternatively, if the viscosity is too low, then the pressure and/ortemperature can be decreased. If the polymer composition is resistant tobeing positioned or placed in a desired location in a desired amount ina given web at various viscosities and/or pressures, then the level offluorochemical pretreatment of the web can be increased, or decreased,as the case may be.

In one embodiment of this invention, polymer is forced into a webbetween two rollers. One such roller bears a polymer impregnant,typically and preferably distributed uniformly upon and over acircumferentially extending textured, or gravure surface. Such rollerrotates (i) in the same direction as a facing roller and (ii) oppositelyto the direction of movement of a continuously moving web traveling pastthe localized pressured area achieved between such roller and suchmoving web. The unidirectional rotation of the two rollers is believedto produce a distorting and stretching force or effect upon the web.This force is believed to promote penetration of the polymer into theweb. This form of pressured application or coating can be termed"reverse roll coating" for convenience. Preferably, the reverse coatingrollers have generally horizontal axis while the moving web movesgenerally horizontally. The web is further concurrently bothlongitudinally tensioned and distorted by being stretched againstmetering bars, bar knives, and the like which are urged against the web.

Such an initial pressured step is preferably followed by a series offurther pressured web treatment steps believed to accomplish polymerreintroduction, polymer distribution, polymer scraping, and excesspolymer removal and recovery. The collective result of such stepsgradually produces a web wherein the polymer envelopes to a desiredextent the fibers, or lines the cell or pore walls comprising the weband collects within a desired internal region or zone in the web therebyfilling or plugging interstitial spaces, or open cells or pores, of theweb in such region, but not filling the internal structure of thetreated web with polymer beyond a desired extent. Particularly, and forexample, in a fabric, a polymer composition may be made to substantiallycompletely envelope the fibers or line the cells or pores thereof andfill the interstitial spaces thereof in such internal region.

In another embodiment of this invention, application of polymer to a weboccurs from a reservoir. This reservoir of polymer is positioned tightlyagainst the tensioned, moving web (or fabric). The linearly extending,preferably vertically upwardly moving, web (or fabric), constitutes awall portion of the reservoir. Next, along the path of web travel, a baror shear knife is pressed strongly and transversely against andlaterally across the longitudinally tensioned web (or fabric). Furtheralong the path of web movement, a shear blade or flexible scraper knifeis also strongly and transversely forced laterally across and againstthe tensioned web. More than one shear knife, or more than one flexiblecompressive knife, can be successively positioned along the path of webmovement. These blade means are believed to reintroduce the polymer intothe web, to distribute the polymer, and to promote and complete theenvelopment of fibers or lining of the cell or pore walls and fillage ofinterstices and open cells with polymer, and form an internal coating ina desired region in a web or encapsulate the fibers, or both. Thesescraper knives or shear blades are also believed to force the polymerfurther into the three-dimensional structure of the web. Also, theseknives, particularly the scraper knives, wipe or scrape excess polymeroff the surface of the web, and also extract polymer from within theweb, thereby regulating the amount of polymer placed within the web.

The transversely applied shear forces applied across and against the webare sufficiently high to achieve temporarily and locally, a lowering ofthe viscosity of the preferably thixotropic viscous polymer. The loweredviscosity polymer is thus enabled to flow into, and upon, the internalthree-dimensional structure of the web. Because the polymer compositionthat is being applied is subject to cure with heat or radiation andtime, and because the pressured placement or shear thinning is believedto produce localized heat, the shearing conditions used prior to curingare preferably controlled to minimize premature curing. The propertiesof the polymer are preferably selected to be such that cure, orexcessive cure, does not occur while the web is being treated withpolymer during the shear thinning and controlled placement. The curepreferably occurs only after the web controlled placement procedure hasbeen completed. Preferably, the cure temperature of the polymercomposition is relatively high (preferably above about 250° F.) and theheat exposure time is such as is needed to obtain a desired solidresilient elastomeric polymer.

The viscosity of the polymer is preferably lowered by the high pressure(shear) forces exerted. However, such a pressure- and/ortemperature-induced lowered viscosity should not go down too low,otherwise the polymer can flow substantially uncontrolled in the web inthe manner of a low viscosity liquid that is saturated and impregnatedinto a web as in prior art web treatments. If the viscosity of thepolymer composition is too low at the time of controlled placement thenthe web interstices or open cells can become excessively filledtherewith, and the polymer is not, for example, reliably andcontrollably applied to achieve an envelopment of the structuralelements (including fibers) of the web being treated together withinternal coating formation.

Benzophenones, and particularly 2,4-dihydroxybenzophenone, are believedto be a particularly useful class of additives to the starting polymercomposition, as hereinbelow described.

As indicated above, the activity transpiring at a final step in thepractice of this invention is generically referred to as curing.Conventional curing conditions known in the prior art for curing polymercompositions are generally suitable for use in the practice of thisinvention. Thus, temperatures in the range of about 250° F. to about350° F. are used and times in the range of about 30 seconds to about 1minute can be used, although longer and shorter curing times andtemperatures may be used, if desired, when thermal curing is practiced.Radiation curing, as with an electron beam or ultraviolet light can alsobe used. However, using platinum catalysts to accelerate the cure whileusing lower temperatures and shorter cure times is preferable.

Since either filled, plugged, almost filled interstices, or open cellsin the region of an internal layer remain transmissive of air in curedwebs made by this invention, the webs are characteristically airpermeable or breathable.

Sample webs or fabrics that are beneficially treated, fiber envelopedand internally coated in accordance with the invention include nylon,cotton, rayon and acrylic fabrics, as well as fabrics that are blends offiber types. Sample nylon fabrics include lime ice, hot coral, raspberrypulp, and diva blue Tactel® (registered trademark of ICI Americas, Inc.)fabrics available from agent Arthur Kahn, Inc. Sample cotton fabricsinclude Intrepid® cotton cornsilk, sagebrush cotton, and light bluecotton fabrics available also from Arthur Kahn, Inc. Non-woven,monofilamentous, fabrics such as TYVEK® (registered trademark of E.I.duPont de Nemours Co., Inc.) and the like are also employable.

As indicated above, a web is preferably pretreated and impregnated witha fluorochemical prior to being treated with a polymer composition astaught herein.

The fluorochemical impregnation is preferably accomplished by firstsaturating a web with a liquid composition which incorporates thefluorochemical, and then, thereafter, removing the excess liquidcomposition and residual carrier fluid by draining, compression, drying,or some combination thereof from the treated web.

It is now believed that any fluorochemical known in the art for use inweb, particularly fabric treatment in order to achieve water repellency,soil repellency, grease repellency, or the like, can be used forpurposes of practicing the present invention. It is believed that atypical fluorochemical of the type used for web treatment can becharacterized as a compound having one or more highly fluorinatedportions, each portion being a fluoroaliphatic radical or the like, thatis (or are) functionally associated with at least one generallynon-fluorinated organic portion. Such organic portion can be part of apolymer, part of a reactive monomer, a moiety with a reactable siteadapted to react with a binder, or the like. Such a compound istypically applied to a fabric or other web as a suspension or solutionin either aqueous or non-aqueous media. Such application may beconventionally carried out in combination with a non-fluorine orfluorine containing resin or binder material for the purpose ofproviding improved durability as regards such factors as laundering, drycleaning, and the like.

Fluorochemicals are sometimes known in the art as durable waterrepellent (DWR) chemicals, although such materials are typicallybelieved to be not particularly durable and to have a tendency to washout from a fabric treated therewith. In contrast, fiber enveloped websof this invention which have been pretreated with a fluorochemicaldisplay excellent durability and washability characteristics. Indeed,the combination of fluorochemical pretreatment and silicone polymerfiber envelopment such as provided by the present invention appears toprovide synergistic property enhancement because the effects orproperties obtained appear to be better than can be obtained than byusing either the fluorochemical or the silicone polymer alone for webtreatment.

Exemplary water repellent fluorochemical compositions include thecompositions sold under the name Milease® by ICI Americas Inc. with thetype designations F-14N, F-34, F-31X, F-53. Those compositions with the"F" prefix indicate that they contain a fluorochemical as the principalactive ingredient. More particularly, Milease® F-14 fluorochemical, forexample, is said to contain approximately 18 percent perfluoroacrylatecopolymer, 10 percent ethylene glycol (CAS 107-21-1) and 7 percentacetone (CAS 67-64-1) dispersed and dissolved in 65 percent water.Milease® F-31X is said to be a dispersion of a combination offluorinated resin, acetone, and water.

Still another suitable class of water repellent chemicals is thePhobotex® chemicals of Ciba/Geigy identified as Phototex® FC104, FC461,FC731, FC208 and FC232 which are each believed to be suitable for use,typically in approximately a 5 percent concentration, in saturating aweb for use in the invention. These and many other water repellentfluorochemicals are believed to be capable of creating a surface contactangle with water of greater than about 90 degrees when saturated into aweb and to be suitable for use in the practice of this invention.

Another group of useful water repellent fluorochemicals is theTEFLON®-based soil and stain repellents of E.I. duPont de Nemours & Co.Inc., 1007 Market Street, Wilmington, Del. 19898. Suitable TEFLON® typesfor use in the practice of this invention include TEFLON® G. NPA, SKF,UP, UPH, PPR, N. and MLV. The active water repellent chemical of eachcomposition is believed to be a fluorochemical in polymeric form that issuitable for dispersion in water, particularly in combination with acationic surfactant as a dispersant. These dispersions are dilutable inall proportions with water at room temperature. One preferred class offluorochemical treating compositions useful in the practice of thisinvention comprises about 1 to about 10 weight percent, more preferablyabout 5 weight percent of one of the above indicated TEFLON®-type waterrepellent fluorochemcials in water.

Another major group of suitable water repellent fluorochemicalcompositions useful in the practice of the invention is commerciallyavailable under the designation ZEPEL® rain and stain repellentchemicals of E.I. duPont de Nemours & Co. Inc., such as ZEPEL® waterrepellent chemicals types B. D, K, RN, RC, OR, HT, 6700 and 7040. Eachis believed to be a fluorochemical in polymeric form that is dispersiblein all proportions at room temperature. The dispersants ZEPEL® B. D, K,and RN are believed to be cationic, while the dispersant ZEPEL® RC isbelieved to be nonionic.

As an exemplary composition, ZEPEL® 6700 is said to be comprised of 15to 20 percent perfluoroalklyl acrylic copolymer, 1 to 2 percentalkoxylated carboxylic acid, and 3 to 5 percent ethylene glycol.Exemplary characteristics of the composition include a boiling point of100° C. at 760 mm Hg and a specific gravity of 1.08. The volatiles areapproximately 80 percent by weight. The pH is 2 to 5. The odor is mild;the concentrate form is that of a semi-opaque liquid; and theconcentrate color is straw white. The composition and characteristics ofZEPEL® 7040 repellent chemical are believed to be substantiallyidentical to those of ZEPEL® 6700 except that the former compositionadditionally contains 7 to 8 percent acetone.

Another major group of water repellent fluorochemicals comprises theScotchgard® water repellent chemicals of 3M Co., St. Paul, Minn. TheScotchgard® fluorochemicals are believed to be aqueously dispersedfluorochemicals in polymeric form. The compositions of two suitableScotchgard® water repellent fluorochemicals are believed to be disclosedin U.S. Pat. Nos. 3,393,186 and 3,356,628, which patents areincorporated herein by reference. Thus, the Scotchgard® fluorochemicalof U.S. Pat. No. 3,356,628 consists of copolymers of perfluoroacrylatesand hydroxyalkyl acrylates. These copolymers are suitable for use as anoil and water repellent coating on a fibrous or porous surface. Theyhave a carbon to carbon main chain and contain recurring monovalentperfluorocarbon groups having from 4 to 18 carbon atoms each and alsohaving recurring hydroxyl radicals. From 20 to 70 percent of the weightof such copolymer is contributed by fluorine atoms in theperfluorocarbon groups and from 0.05 to 2 percent of the weight of thecopolymer is contributed by the hydroxyl radicals. Such copolymer issaid to have improved surface adherability properties as compared to thehomopolymer of a corresponding fluorocarbon monomer.

The Scotchgard® fluorochemical of U.S. Pat. No. 3,393,186 consists ofperfluoroalkenylacrylates and polymers thereof. An exemplary fluorinatedmonomer has the formula: ##STR1##

Wherein R_(f) is a fluorocarbon group having from 3 to 18 carbon atoms,R is hydrogen or methyl, and n is 0-16. Such a water repellentfluorochemical composition is supplied and saturated into the substrateweb as a readily pourable aqueous dispersion.

U.S. Pat. No. 4,426,476 discloses a fluorochemical textile treatingcomposition containing a water-insoluble fluoroaliphatic radical, analiphatic chlorine-containing ester and a water insoluble,fluoroaliphatic radical containing polymer.

U.S. Pat. No. 3,896,251 discloses a fluorochemical textile treatingcomposition containing a fluoroaliphatic radical containing linear vinylpolymer having 10 to 60 weight percent fluorine and a solvent solublecarbodiimide preferably comprising fluoroaliphatic groups. A table inthis patent lists a plurality of prior art fluoroaliphatic radicalcontaining polymers useful for the treatment of fabrics and the priorart patents where such polymers are taught.

U.S. Pat. No. 3,328,661 discloses textile treating solutions of acopolymer of an ethylenically unsaturated fluorocarbon monomer and aethylenically unsaturated epoxy group containing monomer.

U.S. Pat. No. 3,398,182 discloses fluorocarbon compounds useful forfabric treatment that contain a highly fluorinated oleophobic andhydrophobic terminal portion and a different nonfluorinated oleophilicportion linked together by a urethane radical.

Water repellent fluorochemical compositions are preferably utilized tosaturate a starting untreated porous web substrate so that suchcomposition and its constituents wet substantially completely andsubstantially uniformly all portions of the web. Such a saturation canbe accomplished by various well known techniques, such as dipping theweb into a bath of the composition, or padding the composition onto andinto the web, or the like. Padding is the presently preferred method offluorochemical application.

After application of the fluorochemical composition to the web, thewater (or liquid warier) and other volatile components of thecomposition are removed by conventional techniques to provide a treatedweb that contains the impregnated fluorochemical throughout the websubstrate.

In a preferred procedure of fluorochemical controlled placement, a webis substantially completely saturated with an aqueous dispersion of afluorochemical. Thereafter, the resulting impregnated web is compressedto remove excess portions of said dispersion. Finally, the web is heatedto evaporate the carrier liquid. If the fluorochemical is curable, thenthe heating also accomplishes curing. After the fluorochemicaltreatment, the fluorochemical is found only on or in the web structuralelements or fibers and is substantially completely absent from the webinterstices.

The fluorochemical concentration in the treating composition is such asto permit a treated fluorochemical containing web, after volatiles ofthe treating composition are removed, to exhibit a contact angle withwater applied to an outer web surface which is greater than about 90°.More preferably, the contact angle provided is greater than about 130°.

The web weight add-on provided by the fluorochemical after removal ofvolatiles is usually relatively minor. However, the weight add on canvary with such factors as the nature of web treated, the type of polymercomposition utilized in the next step of the process, the temperature atwhich the composition is applied, the ultimate use contemplated for aweb, and the like.

Typical weight add-ons of fluorochemical are in the range of about 1 toabout 10 percent of the original weight of the web. More preferably,such weight add-ons are about 2 to about 4 weight percent of the weightof the starting fabric.

Durability of a web that has been treated with a fluorochemical anddurability of a web that is subsequently treated with a polymer cansometimes be improved by the conventional process of "sintering". Theexact physical and chemical processes that occur during sintering areunknown. The so-called sintering temperature utilized is a function ofthe fluorochemical composition utilized and such temperature isfrequently recommended by fluorochemical manufacturers. Typically,sintering is carried out at a temperature of about 130° to about 160° C.for a period of time of about 2 to about 5 minutes. Acid catalysts canbe added to give improved durability to laundering and dry cleaningsolvents.

The fluorochemical is believed to provide more than water or otherrepellent properties to the resulting treated web, particularly sincethe curable polymer is often itself a water repellent. Rather, andwithout wishing to be bound by theory, it is believed that thefluorochemical in a treated web provides relative lubricity for thetreated fibers during the pressure application of the curable polymer.The polymer is applied under pressures which can be relatively high, andthe polymer is itself relatively viscous, as is discussed herein. Inorder for the curable polymer to coat and envelopweb fibers, but notfill web interstitial voids, the fibers of the web may move over andagainst each other to a limited extent, thereby to permit entry of thepolymer into and around the fibers. It is thought that thefluorochemical deposits may facilitate such fiber motion and facilitateenvelopment during the pressure application and subsequent shearingprocessing.

Alternatively, the fluorochemical may inhibit deposition of the polymerat the positions of the fluorochemical deposits which somehow ultimatelytends to cause thin enveloping layers of polymer to form on fibers.

The precise physics and chemistry of the interaction between thefluorochemical and the polymer is not understood. A simple experimentdemonstrates movement of the liquid polymer as influenced by thepresence of the fluorochemical:

A piece of fabric, for example the Red Kap Milliken poplin polyestercotton blend fabric, is cut into swatches. One swatch is treated with anadjuvant, for example a three percent solution of the durablewater-repellent chemical Milease® F-31X. The treated swatch and anuntreated swatch are each positioned at a 45° angle to plumb. A measuredamount, for example one-half ounce, of a viscous polymer composition,for example the Mobay® 2530A/B silicon composition, is dropped onto theinclined surface of each swatch. The distance in centimeters that thecomposition flows downwards upon the surface of the swatch is measuredover time, typically for 30 minutes.

A graphical plot of the flow of the silicone composition respectivelyupon the untreated and treated swatches over time can be prepared, suchas shown in FIG. 1. At the expiration of 30 minutes the viscouscomposition has typically traveled a distance of about 8.8 centimetersupon the treated swatch, or a rate of about 0.29 centimeters per minute.At the expiration of the same 30 minutes, the viscous composition hastypically traveled a lesser distance of about 7.1 centimeters upon theuntreated swatch, or a rate of about 0.24 centimeters per minute.Qualitatively commensurate results are obtainable with other DWRfluorochemical adjuvants that facilitate the viscous flow of polymercompositions in accordance with the invention. Indeed, if desired, thesimple flow rate test can be used to qualify an adjuvant compound forits employment within the method of the invention. The fluorochemicalpretreated web generally increases the surface contact angle of thepolymer while reducing the amount of saturation of the polymer into thefibers themselves.

The fluorochemical treated web is thereafter treated under pressure witha predetermined amount of a curable polymer composition to form a webwhose fibers are preferably substantially completely enveloped with suchcurable polymer and whose outer surfaces and interstices are preferablysubstantially completely free of the curable polymer. The polymer isthereafter cured by heat, radiation, or the like. Even room temperaturecuring can be used. A polymer impregnated, fluorochemical pretreated webcan be interveningly stored before being subjected to curing conditionsdepending upon the storage or shelf life of the treating siliconepolymer composition.

A curable polymer composition utilized in the practice of this inventionpreferably has a viscosity that is sufficient to achieve an internalcoating of the web. Generally, the viscosity is greater than about 1000centipoise and less than about 2,000,000 centipoise at a shear rate of10 reciprocal seconds. It is presently most preferred that suchcomposition have a viscosity in the range of about 5,000 to about1,000,000 centipoise at 25° C. Such a composition is believed to containless than about 1% by weight of volatile material.

The polymer is believed to be typically polymeric and to be commonly amixture of co-curable polymers, oligomers, and/or monomers. A catalystis usually also present, and, for the presently preferred siliconepolymer compositions discussed hereinafter, is platinum or a platinumcompound, such as a platinum salt.

A preferred class of liquid curable silicone polymer compositionscomprises a curable mixture of the following components:

(A) at least one organo-hydrosilane polymer (including copolymers);

(B) at least one vinyl substituted polysiloxane (including copolymers);

(C) a platinum or platinum containing catalyst; and

(D) (optionally) fillers and additives.

Typical silicone hydrides (component A) are polymethylhydrosiloxaneswhich are dimethyl siloxane copolymers. Typical vinyl terminatedsiloxanes are vinyldimethyl terminated or vinyl substitutedpolydimethylsiloxanes. Typical catalyst systems include solutions orcomplexes of chloroplatinic acid in alcohols, ethers, divinylsiloxanes,and cyclic vinyl siloxanes.

The polymethylhydrosiloxanes (component A) are used in the form of theirdimethyl copolymers because their reactivity is more controllable thanthat of the homopolymers and because they result in tougher polymerswith a lower cross-link density. Although the reaction with vinylfunctional silicones (component B) does reportedly take place in 1:1stoichiometry, the minimum ratio of hydride (component A) to vinyl(component B) in commercial products is reportedly about 2:1 and may beas high as 6:1. While the hydrosilation reaction ofpolymethylhydrosilane is used in both so called RTV (room temperaturevulcanizable) and LTV (low temperature vulcanizable) systems, and whileboth such systems are believed to be useful in the practice of thepresent invention, systems which undergo curing at elevated temperatureare presently preferred.

Elastomers produced from such a curing reaction are known to demonstratetoughness, tensile strength, and dimensional stability.

Particulate fillers are known to be useful additives for incorporationinto liquid silicone polymer compositions. Such fillers apparently notonly can extend and reinforce the cured compositions produced therefrom,but also can favorably influence thixotropic behavior in suchcompositions. Thixotropic behavior is presently preferred incompositions used in the practice of this invention. A terminal silanol(Si--OH) group makes such silanol siloxanes susceptible to reaction incuring, as is believed desirable.

It is believed that all or a part of component B can be replaced with aso called silanol vinyl terminated polysiloxane while using an organotincompound as a suitable curing catalyst as is disclosed in U.S. Pat. No.4,162,356. However, it is presently preferred to use vinyl substitutedpolysiloxanes in component B.

A polymer composition useful in this invention can contain curablesilicone resin, curable polyurethane, curable fluorosilicone, curablemodified polyurethane silicones, curable modified siliconepolyurethanes, curable acrylics, polytetrafluoroethylene, and the like,either alone or in combination with one or more compositions.

One particular type of silicone composition which is believed to be wellsuited for use in the controlled placement step of the method of theinvention is taught in U.S. Pat. Nos. 4,472,470 and 4,500,584 and inU.S. Pat. No. 4,666,765. The contents of these patents are incorporatedherein by reference. Such a composition comprises in combination:

(i) a liquid vinyl chain-terminated polysiloxane having the formula:##STR2## wherein R and R¹ are monovalent hydrocarbon radicals free ofaliphatic unsaturation with at least 50 mole percent of the R¹ groupsbeing methyl, and where n has a value sufficient to provide a viscosityof about 5000 centipoise to about 2,000,000 centipoise at 25° C.;

(ii) a resinous organopolysiloxane copolymer comprising:

(a) (R²)₃ SiO₀.5 units and SiO₂ units, or

(b) (R³)₂ SiO₀.5 units, (R³)₂ SiO units and SiO₂ units, or

(c) mixtures thereof, where R² and R³ are selected from the groupconsisting of vinyl radicals and monovalent hydrocarbon radicals free ofaliphatic unsaturation, where from about 1.5 to about 10 mole percent ofthe silicon atoms contain silicon-bonded vinyl groups, where the ratioof monofunctional units to tetrafunctional units is from about 0.5:1 toabout 1:1, and the ratios of difunctional units to tetrafunctional unitsranges up to about 0.1:1;!

(iii) a platinum or platinum containing catalyst; and

(iv) a liquid organohydrogenpolysiloxane having the formula: ##EQU1## inan amount sufficient to provide from about 0.5 to about 1.0silicon-bonded hydrogen atoms per silicon-bonded vinyl group of abovecomponent (i) or above subcomponent (iii) of, R_(a) is a monovalenthydrocarbon radical free of aliphatic unsaturation, and has a value offrom about 1.0 to about 2.1, b has a value of from about 0.1 to about1.0, and the sum of a and b is from about 2.0 to about 2.7, there beingat least two silicon-bonded hydrogen atoms per molecule.

Optionally, such a composition can contain a finely divided inorganicfiller (identified herein for convenience as component (v)).

For example, such a composition can comprise on a parts by weight basis:

(a) 100 parts of above component (i);

(b) 100-200 parts of above component (ii);

(c) a catalytically effective amount of above component (iii), which,for present illustration purposes, can range from about 0.01 to about 3parts of component (iii), although larger and smaller amounts can beemployed without departing from operability (composition curability) asthose skilled in the art will appreciate;

(d) 50-100 parts of above component (iv), although larger and smalleramounts can be employed without departing from operability (curability)as those skilled in the art will appreciate; and

(e) 0-50 parts of above component (v).

Embodiments of such starting composition are believed to be availablecommercially from various manufacturers under various trademarks andtrade names.

As commercially available, such a composition is commonly in thetwo-package form (which are combined before use). Typically, thecomponent (iv) above is maintained apart from the components (i) and(ii) to prevent possible gelation in storage before use, as thoseskilled in the art appreciate. For example, one package can comprisecomponents (i) and (ii) which can be formulated together with at leastsome of component (ii) being dissolved in the component (i), along withcomponent (iii) and some or all of component (v) (if employed), whilethe second package can comprise component (iv) and optionally a portionof component (v) (if employed). By adjusting the amount of component (i)and filler component (v) (if used) in the second package, the quantityof catalyst component (iii) required to produce a desired curablecomposition is achieved. Preferably, component (iii) and the component(iv) are not included together in the same package. As is taught, forexample, in U.S. Pat. No. 3,436,366 (which is incorporated herein byreference), the distribution of the components between the two packagesis preferably such that from about 0.1 to 1 part by weight of the secondpackage is employed per part of the first package. For use, the twopackages are merely mixed together in suitable fashion at the point ofuse. Other suitable silicone polymer compositions are disclosed in thefollowing U.S. patents:

U.S. Pat. No. 4,032,502 provide compositions containing a linearpolydiorganosiloxane having two siloxane bonded vinyl groups permolecule, organosiloxane that is soluble in such linearpolydiorganosiloxane and comprised of a mixture of a polyorganosiloxaneand a polydiorganosiloxane, platinum-containing catalyst, a platinumcatalyst inhibitor, and a reinforcing silica filler whose surface hasbeen treated with an organosilicone compound.

U.S. Pat. No. 4,108,825 discloses a composition comprising atriorganosiloxy end-blocked polydiorganosiloxane, anorganohydrogensiloxane having an average of at least 2.1 silicon-bondedhydrogen atoms per molecule, a reinforcing silica filler having asurface treated with an organosilicone compound, a platinum catalyst,and ceric hydrate. Such silicone polymer composition is desirable when aweb is being prepared which has flame retardant properties.

U.S. Pat. No. 4,162,243 discloses a silicone composition of 100 parts byweight triorganosiloxy end-blocked polydimethylsiloxane, reinforcingamorphous silica that is surface treated with organosiloxane groups,organohydrogensiloxane, and platinum catalyst.

U.S. Pat. No. 4,250,075 discloses a liquid silicone polymer compositionthat comprises vinyldiorganosiloxy end-blocked polydiorganosiloxane,polyorganohydrogensiloxane, platinum catalyst, platinum catalystinhibitor, and carbonaceous particles. Such a silicone polymercomposition is useful when a web of this invention is being preparedthat has electrically conductive properties.

U.S. Pat. No. 4,427,801 discloses a curable organopolysiloxane of liquidtriorganosiloxy end-blocked polydiorganosiloxane wherein thetriorganosiloxy groups are vinyl dimethylsiloxy orvinylmethylphenylsiloxy, finely divided amorphous silica particlestreated with mixed trimethylsiloxy groups and vinyl-containing siloxygroups, organopolysiloxane resin containing vinylgroups,organohydrogensiloxane, and a platinum containing catalyst.

U.S. Pat. No. 4,500,659 discloses a silicone composition of liquidtriorganosiloxy end-blocked polydimethylsiloxane wherein thetriorganosiloxy units are dimethylvinylsiloxy ormethylphenylvinylsiloxy, a reinforcing filler whose surface has beentreated with a liquid hydroxyl end-blocked polyorganosiloxane which isfluorine-substituted, a liquid methylhydrogensiloxane, and aplatinum-containing catalyst.

U.S. Pat. No. 4,585,830 discloses an organosiloxane composition of atriorganosiloxy end-blocked polydiorganosiloxane containing at least twovinyl radicals per molecule, an organohydrogensiloxane containing atleast two silicone-bonded hydrogen atoms per molecule, aplatinum-containing hydrosilation catalyst, optionally a catalystinhibitor, a finely divided silica filler, and a silica treating agentwhich is at least partially immiscible with said polydiorganosiloxane.

U.S. Pat. No. 4,753,978 discloses an organosiloxane composition of afirst diorganovinylsiloxy terminated polydiorganosiloxane exhibiting aspecified viscosity and having no ethylenically unsaturated hydrocarbonradicals bonded to non-terminal silicon atoms, a seconddiorganovinylsiloxy terminated polydiorganosiloxane that is misciblewith the first polydiorganosiloxane and contains a vinyl radical, anorganohydrogensiloxane, a platinum hydrosilation catalyst, and a treatedreinforcing silica filler.

U.S. Pat. No. 4,785,047 discloses silicone elastomers having a mixtureof a liquid polydiorganosiloxane containing at least two vinyl or otherethylenically unsaturated radicals per molecule and a finely dividedsilica filler treated with a hexaorganodisilazane which mixture is thencompounded with additional hexaorganodisiloxane.

U.S. Pat. No. 4,329,274 discloses viscous liquid silicone polymercompositions that are believed to be suitable and which are comprised ofvinyl containing diorganopolysiloxane (corresponding to component B),silicon hydride siloxane (corresponding to component A) and an effectiveamount of a catalyst which is a halogenated tetrameric platinum complex.

U.S. Pat. No. 4,442,060 discloses a mixture of 100 parts by weight of aviscous diorganopolysiloxane oil, 10 to 75 parts by weight of finelydivided reinforcing silica, 1 to 20 parts by weight of a structuringinhibitor, and 0.1 to 4 parts by weight of 2,4-dichlorobenzoyl peroxidecontrolled cross-linking agent.

Silicone resin compositions shown in Table I below have all been used inthe practice of this invention. Such compositions of Table I arebelieved to involve formulations that are of the type hereinabovecharacterized.

                  TABLE I    ______________________________________    Illustrative Starting Polymer Compositions    MANU-     TRADE    FACTURER  DESIGNATION  COMPONENTS    ______________________________________    Mobay     Silopren ®                           Vinyl-terminated polydimethyl-              LSR 2530     siloxane with fumed silica,                           methylhydrogen polysiloxane    Mobay     Silopren ®              LSR 2540/01    Dow Corning              Silastic ® 595 LSR                           Polysiloxane    General Electric              SLE 5100     Polysiloxane    General Electric              SLE 5106     Siloxane resin solution    General Electric              SLE 5300     Polysiloxane    General Electric              SLE 5500     Polysiloxane    Shin-Etsu KE 1917    Shin-Etsu DI 1940-30    SWS Silicones              Liquid Rubber                           Silicone fluid with silicone    Corporation              BC-10        dioxide filler and curing agents    GE SLE 5110            Polysiloxane    GE SLE 6108            Polysiloxane    ______________________________________     Table I footnote: (1) Identified components do not represent complete     composition of the individual products shown.

When a polymer composition of a silicone polymer and a benzophenone ispressured into a porous web as taught herein, protection of an organicweb against ultraviolet radiation is improved, and the degradationeffects associated with ultraviolet light exposure are inhibited, as maybe expected from prior art teachings concerning the behavior ofbenzophenones.

Surprisingly and unexpectedly, however, when silicone polymercompositions such as used in this invention contain a benzophenone, theresulting composition is believed to display improved viscositycharacteristics, particularly thixotropic characteristics, and alsocuring acceleration, when such a composition is subjected to high shearforces.

A presently preferred benzophenone additive useful in the presentinvention is 2,4-dihydroxygenzophenone.

The regulation of internal and external rheology, and of viscosity,achieved in a characteristically highly viscous polymer composition ofthe invention is believed to be an important and desirable feature ofthe benzophenone and silicone polymer compositions which find use ininternally coated web manufacture as taught herein.

In such compositions useful in the present invention, a control ofcompositional rheology, and particularly of complex viscosity, isaccomplishable, if desired, by the selective addition of diluent andadditives. These polymer compositions characteristically exhibitperformance curves indicating substantially level and constant lossmodulus, storage modulus, and complex viscosity over extendedtemperature ranges. The graphic plots of loss modulus, storage modulus,and complex viscosity versus temperature all are believed tocharacteristically exhibit a sharp knee that shows the moduli toincrease in value rapidly at cure temperatures.

Preferably, the curing proceeds to a point where the polymer compositionis no longer sticky, or tacky, but preferably curing is not allowed tocontinue to a point where the resulting polymer composition becomesexcessively hard, rigid, or brittle. Compositions of this invention arecontrollably curable into polymeric materials which are preferably notsticky or tacky, and which have desirable elastomeric, flexural, andresiliency characteristics.

The contact angle exhibited by a silicone composition used in thisinvention varies with the particular web which is to be saturatedtherewith. However, the contact angle of water is generally lower forthe non-treated side than the treated side. A combination of theprocessed web, the silicone polymer and the fluorochemical generallyproduces higher water contact angles than webs treated only withfluorochemicals. The performance of a polymer composition may bedetermined by the nature of a previously applied saturant such as afluorochemical. Suitable starting compositions include 100% liquidcurable silicone rubber compositions, such as SLE5600 A/B from GeneralElectric, Mobay LSR 2580A/B, Dow Corning Silastic® 595 LSR and Silastic®590 which when formulated with substituted benzophenone as taught hereinwill form a contact angle of much greater than 70 degrees, and typicallyof 90+ degrees, with typical porous webs (such as fabrics) that have aresidue of fluorochemical upon (and within) the web from a priorsaturation.

The polymer composition used in the practice of this invention can alsocarry additives into the three-dimensional structure of the web duringthe pressured application. Further, it is preferable, that any additivesbe bound into the cured composition permanently as located in thethree-dimensional structure of the web. Particularly in the case offabrics, this desirably positions the additives mainly on surfaceportions of the encapsulated yarns and fibers in positions where theytypically are beneficially located and maintained, or on the surfaces ofthe internal layer, or on the surfaces of the web, or some combinationthereof.

Control of the pressurized application step can be provided at a numberof areas since the shear process is sensitive to the viscosity of thepolymer composition both at atmospheric pressure and at superatmosphericpressure. The ambient temperature affecting the polymer as it isapplied, and the pressure-induced temperature changes occurring duringcontrolled placement of the polymer also play roles in viscosity andtherefore the shear process. Of course, the chemical composition of thepolymer composition also plays a role in the shear process and assistsin the formation of an internal layer and/or internal encapsulation ofthe fibers or structural elements of the web.

The amount of polymer utilized and the weight add-on thereof are againvariable and dependent upon several things such as the treated web, thedesired end use of the web, cost and the like. Web weight add-ons can beas little as about 5 weight percent up to about 200 weight percent ofthe untreated web. For producing breathable, water-repellent fabric websof this invention, weight add-ons are preferably in the range of about10 to about 100 weight percent of the weight of the untreated web.

The fluorochemical saturant composition may also contain a bondingagent. The bonding agent can facilitate the bonding of the waterrepellent chemical and/or the impregnate to the three-dimensionalstructure of the web within which it is saturated. Mobay Silopren™bonding agent type LSR Z 3042 and Norsil 815 primer are representativecompositions that can be used to facilitate bonding of the waterrepellent chemicals and/or impregnant to and within the web. Use of thebonding agents is not essential to the practice of this invention, butmay improve bonding of the fluorochemical and/or the polymer compositionto fibers.

The fluorochemical particularly, and also the bonding agents when used,are preferably affixed to the three-dimensional structure of the webprior to the controlled placement of polymer within the web. Completeaffixing is not necessary for the fluorochemical. The fluorochemicalwill apparently facilitate the pressured application of a polymercomposition even if the fluorochemical is not preliminarily fixed withinor located within the web being treated. However, fixing, especially bysintering, appears to cause the water repellent chemicals to flow and tobecome better attached to the three-dimensional structure of the web. Inthis regard, a lesser amount of fluorochemical will remain in placebetter, and will better facilitate the subsequent pressured applicationof the polymer, if the sintering or insolubilizing step is performedprior to such a pressured application.

After fluorochemical saturation followed by controlled polymer placementand curing, a web may have a surface contact angle with the polymer ofgreater than about 70 degrees, and more typically greater than about 90degrees. Web pressures can involve transverse force or pressure in therange of tens to thousands of pounds per square inch of web surface.

Similar to the functional qualifications achieved by the use of afluorochemical in the preferred saturating pretreatment step, thepolymer introduced by the pressured application step can be defined byits functional qualifications. For example, the silicone polymerproduces a contact angle with a fluorochemical treated web of greaterthan about 70 degrees. The contact angle of a web with a fluorochemicalwill be within a range of about 90 degrees to about 180 degrees whilethe contact angle of a fluorochemically treated web with the siliconepolymer will be within a range of about 70 degrees to about 180 degrees.

The contact angle exhibited by the silicone polymer can be, if desired,qualified against the particular web saturated with the particularfluorochemical saturant. The selection of a suitable silicone polymercomposition may be determined by the nature of the previously appliedfluorochemical saturant. The fluorochemical saturant and siliconepolymer compositions are, however, not critical to the practice of thisinvention since wide respective compositional ranges may be involved. Inparticular, a substantially undiluted liquid silicon rubber which isavailable from suppliers, such as GE, Dow Corning, and Mobay-Bayer, willcharacteristically form a contact angle of much greater than about 70degrees, and typically greater than about 90 degrees, with typicalporous webs (such as fabrics) that have a residue of fluorochemical upon(and within) the web resulting from a prior saturation.

The polymer composition can carry additives into the three-dimensionalstructure of the web in the pressured application steps of the method ofthe invention. Further, the polymer composition, when cured, is capableof adhering to structural elements, fibers, yarns, and the like, and anyadditives dispersed therein. Thus, additives are positioned adjacent toor on surfaces of structural elements, yarns, fibers and the like, in aposition where they can be beneficial.

Examples of additives that are dispersible in effective amounts in aviscous polymer composition typically at a concentration of about 0.1 to20 weight percent (based on total composition weight) includeultraviolet absorbers, flame retardants, aluminum hydroxide, fillingagents, blood repellents, flattening agents, optical reflective agents,hand altering agents, biocompatible proteins, hydrolyzed silk, and thelike. Hydrolyzed silk is a texturing agent that imparts a substantiallysilky feel to a fabric treated in accordance with the method of theinvention regardless of whether or not such treated web or fabric isitself silk.

Examples of other polymer dispersible agents include those affectingthermal conductivity, radiation reflectivity, electrical conductivity,and other properties. For example, if a metallic sheen and/or thermal orelectrical conductivity or infrared background blending is desired,powdered metals may be dispersed therein.

The pressured application of the polymer is sensitive to the viscosityof the polymer composition. Temperature affects the polymer compositionby reducing or altering its viscosity. Shear-induced temperature changesoccurring during application or during subsequent shear processing ofthe polymer can affect viscosity. The chemical composition of thepolymer also plays a role in the treating process and effects in thetreatment of web structural elements (including fibers) and theregulation of the filling of interstices and open cell voids.

Various machines and procedures can be used for performing the processof the invention. Illustrative machines and processes of use which aresuitable for use in the practice of this invention, are now described.

An embodiment of apparatus in accordance with this invention isillustrated in the side elevational view in FIG. 4a. Two blades 200 and210 in opposed relationship to one another are provided in functionalcombination with means for providing a precisely adjustable gaptherebetween through which a web or fabric 300 is drawn while having apolymer composition 220 applied to either one or both surfaces thereof.An enlarged side view of a typical blade 200 or 210 is shown in FIG. 4b.Dimensions A, B,C, D, and E are typically and exemplarily illustratedas, respectively, about 31/2 inches, about 11/2 inches, about 2 inches,about 1/2 inch, and about 5/16 inch. The narrow edge is preferablymilled to a tolerance of about 1/10,000 inch continuously along the edgesurface of each blade which is typically and illustratively about 38inches long. Each of the corners of the narrow edge is preferably andillustratively a hard (not beveled or ground) angular edge. Each blade200 or 210 is typically and illustratively made from carbon steel orstainless steel. The entry angle of the web 300 with the blade isgenerally not altered in the apparatus of FIG. 4a. Therefore, forpurposes of the apparatus illustrated in FIG. 4a, the blade shown inFIG. 4b has a leading edge 260 and a trailing edge 250.

A reservoir of polymer composition is formed preferably on one uppersurface of the web or fabric 300 behind (relative to the direction ofweb movement) an upper one of the blades 200 and 210 which are mountedon a frame (not shown) so as to extend horizontally. As the fabric 300is drawn through the slit orifice defined between blades 200 and 210,some polymer becomes entrained on the web or fabric surface and movesthrough such slit orifice, thereby accomplishing pressurized applicationof the polymer into the web or fabric 300. The slit orifice gap ischosen preferably and illustratively to be slightly smaller than therelaxed thickness of the starting web or fabric.

Referring to FIG. 4a, a second pressured application station is seen tobe positioned downstream (relative to the direction of fabric movement)from the pair of opposed blades 200 and 210. While the blades are shownpositioned directly opposed to one another, they may be offset so thatthe advancing web first contacts one blade and then the other. In such aconfiguration, the blades may also be adjusted to some angle other than90° to the web, and blade adjustment facilities (not shown) can be usedto accomplish this. At this station, a knife blade 230 is provided whichhas an edge that presses against the web or fabric 300 to reintroducethe polymer composition into the fabric 300. One side of blade 230,adjacent to the edge thereof, is strongly biased against an adjacentcylinder or bar 240, which, in the embodiment shown, does not rotate. Ifdesired, bar 240 can be journaled for rotational movement. As the fabricis moved between the blade 230 and the bar 240, it is preferablyuniformly compressed. Preferably, the compression force is in the rangeof about 10 to about 500 pounds per linear inch, although higher andlower forces can be employed. As the fabric 300 passes over the edge ofblade 230, it is drawn away at an angle from the blade edge underlongitudinal tension. For example, longitudinal tension in the range offrom about 0.5 to 10 pounds per inch can be employed. Such pressuredapplication or controlled placement serves to distribute and reintroducethe polymer composition in the web. Excess polymer composition isremoved by blade scraping. Passage of the fabric 300 between the blade230 and the bar 240 and over the edge of the blade 230 is believed toproduce shear forces in the polymer composition 220 (within the fabric300) that facilitate flow and distribution thereof within thethree-dimensional matrix of the fabric 300. Concurrently, blade 230 alsoscrapes excess polymer composition off the fabric's surface in contactwith the edge of blade 230.

Both the steps of fluorochemical saturation and of subsequent polymercomposition controlled placement are performable, if desired, inproduction volumes, and at speeds which can be typical of the so-calledhigh end range of fabric finishing lines. The fluorochemical saturationis conveniently accomplished conventionally by using a padbath in whichthe fabric is run through a dilute treating bath followed by squeezerollers to remove excess liquid and overdrying. In general, any methodof applying the fluorochemical would be acceptable. Typically, the webis treated with a fluorochemical and wound on a roll before it isintroduced into apparatus of this invention apparatus although, ifdesired, the fluorochemical treatment could be in-line.

Another embodiment of a machine suitable for accomplishing controlledplacement of polymer within a web in accordance with this invention isshown diagrammatically in FIG. 5. At a treatment or control head,pressurized introduction of the polymer composition into the web isfirst carried out. At a subsequent stage, controlled pressurereintroduction, distribution, and metering of the polymer compositionand recovery of excess polymer transpires using a shear knife or bladewhich applies transverse force against the treated web laterally acrossthe web. In a subsequent stage, further controlled pressurereintroduction and metering takes place by means of another blade,either flexible or rigid, such as, for example, a so-called flex-knifeor Spanish knife. Here, additional recovery of excess liquid polymer isaccomplished.

In all knife-applying states, the excess polymer removed is collectedand preferably passed by a recycling system back to the initial,pressured introduction stage to achieve process operating economies.Still further successive polymer pressure reintroduction stages may beused if desired. The direction of the arrows in the diagrammaticrepresentation of FIG. 5 shows the general direction of movements in theregion of the treatment head, including the general direction of polymermovement in the practice of such process.

The apparatus employed in the present invention functions first to applyand preferably concurrently to shear thin and place a polymercomposition into a web under pressure. Such polymer composition is thenreintroduced, distributed, and metered in a controlled manner in the webwith the aid of transversely applied shearing force and compressiveforce such that the polymer composition becomes distributed in the webso that an internal layer of polymer is formed while the fibers are atleast partially enveloped while the interstices or open cells aresubstantially completely filled with the polymer composition in theregion of the internal coating, and/or the fibers within the web arepartially or fully encapsulated. During treatment, the web islongitudinally tensioned and the pressurized application and thesubsequent shearing and compressive actions are successivelyaccomplished in localized zones preferably extending generally laterallyacross the web (that is, generally perpendicularly to the direction ofsuch longitudinal web tensioning) using transversely applied forceexerted locally against surface portions of the web during eachcontrolled placement and shearing operation. The web is conveniently andpreferably, but not necessarily, moved longitudinally relative to suchlaterally extending web processing zones. In treating short lengths of afabric, the blades may be moved relative to a stationary length offabric. The pressurized application, shearing and compressing steps arepreferably carried out successively or sequentially. Such zones arethemselves preferably at stationary locations while the web is moved,but if desired, the web can be stationary while the zones are moved, orboth. The result is that the polymer composition flows into the web andis distributed internally generally uniformly to a predeterminable andcontrollable extent.

A schematic side elevational view of another embodiment of a suitablemachine for use in the practice of the invention is shown in FIG. 6.This machine continuously moves a longitudinally tensioned web 60successively through a pressure station which incorporates a reverseroll coater having rollers 10 and 11, a shear station which incorporatesa shear knife 20, and a finishing station which employs at least one socalled flex-knife (or Spanish knife) 30. A typical shear knife isillustratively shown in FIG. 4b. for purposes of the apparatus shown inFIG. 6, the knife shown in FIG. 4b has a leading edge 250 and a trailingedge 260. Optionally, but preferably (for reasons of process operatingeconomics) excess polymer composition that is removed from web surfacesin the shear station and finishing station is returned to the pressurestation for reuse using liquid recovery and recycle system 40. In thepressure station, polymer 50 is contained within reservoir 51. Roller 12rotates in the indicated direction so that its circumferential surface,preferably a textured or gravure surface, picks up liquid 50 fromreservoir 51 and deposits it on the circumferential surface of roller 10across a controlled width gap 13 between rollers 10 and 12. Typically,gap 13 is actually less than the unencumbered thickness of the startingweb 60. Roller 10 also preferably has a textured or gravure surface.Roller 10, rotating in the roller arrow indicated direction, which isopposite to the direction of travel of web 60, applies the polymer toone surface of the moving web 60, which is typically a fabric. Roller 11is urged with a compressive force against the back or opposed surface ofweb 60 and roller 11 rotates in a direction which is the same as that inwhich web 60 travels. Roller 11 aids in achieving the desired pressuredapplication of polymer into web 60 from the surface of roller 10.

Referring to FIG. 6, the polymer is believed to be introduced into theweb and into the interstices or open cells of the web 60 by the aid of aback-pulling or shearing action resulting from the distorting andpressuring of web 60 caused by rollers 10 and 11 rotating in the samedirection. This direction may be the indicated direction with roller 10rotating against the linear movement of web 60 indicated by webdirectional arrow 61, or all rollers 10, 11 and 12 may be reversed inrespective rotational direction so as to cause each roll to turn in anopposite direction relative to that direction which is illustrated bythe respective roller arrows in FIG. 6. Regardless of which side of web60 is back-pulled or subjected to shearing action by a reverse rotatingroller, the web 60 is stretched and distorted to pull open theinterstices of the web and to aid in forcing polymer 50 into the web 60.This distorting, and particularly this stretching, is believed tofacilitate the full and deep introduction of the polymer into the movingweb 60. However, it is to be understood that use of a reverse rollcoater or other facilities which distort the web at the polymerapplication stage is not required. Other suitable polymer applicatorswell known in the art may be used to deposit the polymer on the surfaceof the web. Thereafter, the polymer may be shear thinned and placed intothe web by use of one or more shear knives 20.

The extent of pressured application of the polymer 50 into the web 60which occurs between rotating rollers 10 and 11 is controllable to someextent by such variables as the speed of roller rotation, the pressureexerted by rollers 10 and 11 on web 60, the durometer hardness andsurface characteristics of each roll 10 and 11 (particularly of thepreferred textured or gravure surface of roll 10). However, thepressurized application may also be carried out with rollers 10 and 11which have finely milled, smooth circumferential surfaces. The viscosityof polymer 50 and the amount of polymer 50 transferred from roll 12 toroll 10 across gap 13 may also be varied to regulate controlledplacement of polymer within the web. Feed roller 12 preferably rotatescounter to application roller 10. The polymer 50 can be monitored toassure that its homogeneous composition is maintained. If desired, thepolymer composition 50 can be altered to adjust to process needs duringa continuous treating operation.

The result of the introduction of the polymer 50 into the web 60 whichis accomplished between rollers 10 and 11 using a polymer composition50, which can have the viscosity or consistency of a conventionalbathtub caulk composition, is to produce a web 60, or fabric, whoseinterstices or open cells are substantially completely filled withpolymer in the region of the internal layer, or to produce a web havingits structural elements or fibers encapsulated, or to produce a webhaving a combination of an internal layer and encapsulated fibers. Forexample, in the case of a fabric, the region of the internal layer canbe such that spaces (i.e., interstices or open cells) between thefabric's fibers/filaments, or the fabric's yarn members (as the case maybe) are filled with polymer 50. However, the amount of polymer 50 whichis thus introduced into web 60 can be much less than a saturation level;for example, if desired, the amount introduced can be insufficient evento coat or substantially completely envelope individual fibers of theweb. Actually, the polymer 50 can be relatively non-uniformlydistributed in the web after such pressurized application. The action ofthe shear knife 20 in the next zone of processing is such as to smoothout and to make uniform the distribution of polymer 50 in web 60. Also,the shear knife 20 helps regulate the amount of polymer 50 that isallowed to remain in web 60. While one shear knife is shown, it may bedesired use a plurality of such knives in sequence to provide a seriesof shear thinning stations.

After the shear zone, if desired, a top coat polymer can additionally beintroduced; for example, just before or after a flex knife 30. Byovercoating for example, the original polymer with a dilute or very thinsecond or top coat, a more tightly cross linked encapsulated orenveloped product may be achieved, or surface properties of the productcan be varied or improved. For example, the top coating can comprise adilute dispersion of a fluorochemical fabric treating composition. In aweb treated therewith, such treatment enhances surface properties of theweb, such as by increasing grease or chemical penetration resistance, orsoil resistance, or the like. The dilute fluorochemical dispersion canbe applied by spraying, misting, or the like. Both treating agents thenenter a curing stage, which can be accomplished conveniently by passingthe treated web through an oven wherein the temperature and webresidence time are sufficient to cure both the fluorochemical andpolymer compositions to a desired extent, or by radiation, if desired.

The amount of polymer composition actually introduced through thecontrolled placement, and into the preferably stretched openings of theinterstices of the web 60 is influenced by such factors as the velocityof movement of web 60, the viscosity characteristics of polymer 50, thecompressive pressure exerted by roll 10 against roll 11, thelongitudinal tension exerted upon the tensioned web 60, the force ofblade 20 against the web, the angle of blade 20 relative to the web, thenumber of shear blades used, the polymer distribution achieved by shearblade 20 and by scraper flex knive(s) 30, and the like. In particular,the polymer reintroduction and distribution believed to be achieved bybar or shear knife 20 is achieved by the exertion of a pressure againstmoving tensioned web 60. The shear force and the temperature elevationdue to such shear force results in the polymer 50 flowing into thethree-dimensional structure of the web 60.

Preferably, the polymer 50 is thixotropic. The flowing of the polymer 50into the web 60 using controlled liquid rheology preferably does notresult at the time of controlled placement in a fluid viscosity which isso low as to cause the impregnant to spread into and be distributedsubstantially uncontrolled throughout the web 60. However, the flowingactivity of the polymer is preferably accomplished using a polymer 50which has a controllable rheology and viscosity such that a polymer 50will achieve a desired internal layer and/or envelopment of individualfibers of the web 60. Particularly when the web 60 is a fabric, thisenvelopment is preferably a surrounding of the fabric's individualfibers with a localized layer or film of polymer while an internal layeris formed.

A plurality of web tension control devices 10 can be used in the regionof metering bar or shear knife 20 and in the region of reintroductionscraper flex knives 30 along web 60 in order to provide the capacity forprecision control of the tension exerted on web 60 and of thecompressive pressures and shear forces exerted on web 60 at the meteringbar or shear knife 20 and flexible knives 30.

As shown in FIG. 6, the machine preferably includes an polymer 50recovery and recycling system which more preferably also includes afiltering subsystem, such system being diagrammatically represented andindicated by line path 40. This system includes a collection tray, orpan, 41, positioned under and behind the moving web 60 to collect alongthe sides of web 60, the excess impregnating liquid as it is wiped fromthe web surface contacted by the shear knife 20 and/or by the recoveryknives 30 and passed laterally into pan or tray 41. From the recoverycollection tray 41, the excess polymer 50 is pumped back through afilter (not shown) into the reservoir 51 of the reverse roll coater forloading and distribution on the surface of roller 12, transfer to roller10, and reapplication to portions of continuously moving web 60. Theability to reuse the excess polymer 50 wiped from the moving web 60rather than losing such polymer within the process makes the entireprocess more economically attractive.

Another embodiment of a machine in accordance with this invention isshown schematically in side elevation in FIG. 7. In this embodiment,rollers 10 and 11 of the FIG. 6 methods and apparatus are replaced witha combination of a reservoir 51, and one or more bars or shear knives100. A typical shear knife is illustratively shown in FIG. 4b. Forpurposes of the apparatus shown in FIG. 7, the knife shown in FIG. 4bhas a leading edge 250 and a trailing edge 260. The reintroduction baror shear knife 100 shear thins the polymer 50 which is applied ordeposited onto the moving web 60 from the reservoir 51 as a liquid orbath. The web 60 in effect constitutes a retaining wall for a part ofthe reservoir 51. The reservoir 51 thus functions to hold a pool of thepolymer composition 50 against a surface of the moving web 60 which inthe embodiment shown, is moving vertically upwardly. The bar or shearknife 100 functions to apply pressure or force upon the polymercomposition polymer 50 that was deposited on the web 60, thereby toshear thin the polymer 50 and cause it to penetrate the web 60. Theknife 100 also serves to distribute and move the polymer in the web andto accomplish envelopment of the fibers thereof. Excess polymer 50 isalso scraped away by knife 100. Optionally, one or more of flexible orrigid knives 100 function to further reintroduce and distribute thepolymer 50 and to envelope fibers of web 60 while forming an internalpolymer layer within the web, or to produce a web having its structuralelements or fibers encapsulated, or to produce a web having acombination of an internal layer and encapsulated fibers. The knives 110can be considered to function in a manner which is equivalent to theknives 30 on the treated surface of web 50 in the FIG. 6 methods andapparatus.

Typically, any polymer scraped from the moving web 60 by bar knife 100falls directly back into the reservoir 51. Polymer scraped from themoving web 60 by scraper knife 110 is collected in sloping trough 120and returned by falling along the indicated dotted line path to thereservoir 51. Longitudinal tension control of the moving web 60 isregulated by tension control devices 70 (such as a series of rollers)from a region beginning after reservoir 51 and extending to an oven 80along the path of web 60 travel.

Relative to the FIG. 7 embodiment, the FIG. 6 embodiment is believed toexhibit a wider degree of control in the practice of the presentcontrolled placement process. Particularly, both the initial appliedamount and the successive pressurings of, a polymer 50 are preciselycontrollable. Relative to the FIG. 6 embodiment, the FIG. 7 embodimentis characterized by the capability for operation at higher web 60transport speeds, typically at speeds characteristic of higher endcommercial fabric finishing line operations. The embodiment shown inFIG. 6 is believed to be suitable for producing internally coatedfabrics when the fabrics are of the thicknesses characteristic ofgarments, and where deeply controlled pressured placement over distancesextending perpendicularly into and through a web of fabric greater thanabout 1/16 inch is not generally required.

FIG. 12a depicts a schematic, side elevational view of another methodand apparatus for practicing the present invention. In this method andapparatus, a continuous web 74 is moved along a web pathway from asupply roll 76 to a take-up roll 77.

In a first functional processing station 78, a polymer composition isapplied to the upper face 79 of web 74 by a polymer applicator such as aconventional reverse roll coater 81. In the reverse roll coater 81, thepolymer composition is applied to the surface of a reversely rotating(relative to the direction of travel of web 74) coating roll 82 from anip region reservoir 83 formed between the coating roll 82 and atransfer roll 84 (which rotates in the direction of travel of web 74,but whose surface does not contact web 74). The web 74 is transverselycompressed between coating roll 82 and drive roll 86 as it passesthrough station 78. Thus, the polymer composition is applied under apositive pressure against face 79 by coating roll 82 which functions tocause the composition to be forced into web 74. A present preference isto use a coating roll 82 which has smooth, chrome plated surfaces. It isalso possible to apply the polymer composition to the upper face 79 ofthe web 74 without any force, leaving the controlled placement and shearthinning for a subsequent step or series of steps, such as by the forceof the shear knives as described below.

Largely for purposes of controlling the alignment of web 74 with rolls82 and 86, the web 74 is pretensioned by coating clutching rolls 87, 88and 89. After the web 74 passes over guide roller 91 on the web pathwayfrom supply roll 76, the web 74 passes over roll 87, between rolls 87and 88, around roll 88, and between rolls 88 and 89. The clutching rolls87, 88 and 89 are components of a conventional web clutching mechanism(not detailed) which provides for adjustments between rolls 87, 88 and89 so that selective tensioning of web 74 is achieved along the webpathway between the clutching rolls 87, 88 and 89 and the nip region 92defined between rolls 82 and 86 with the intervening roller roll 93being used for guidance of web 74. The clutching rollers 87, 88 and 89also function to smooth out and extend web 74 before it enters thecoater methods and apparatus 81 so that in the methods and apparatus 81,the web will have polymer composition uniformly applied thereto.

After passing nip region 92 the web 74 is controllably longitudinallytensioned along the web pathway extending from nip region 92 tocompensating and regulating coating tension rollers 94, 95 and 96. Thetension rollers 94, 95 and 96 are components of a conventional webtension adjusting and regulating mechanism (not detailed) which providesfor on-line, in-stream operator controlled adjustments between rollers94, 95 and 96 that permit selective control of the tautness of web 74particularly in the web pathway region from nip region 92 to rollers 94,95 and 96. In the event a reverse roll coater is not utilized, thetension will be controlled in the region between rolls 87, 88 and 89 onone hand, and rolls 94, 95 and 96 on the other hand.

Along the tensioned web pathway region, the web 74 successively passesthrough each one or more of a series of processing stations 98, 99 and100. While three processing stations are shown, more or less could beutilized in accordance with this invention. At each of the stations 98and 99, a substantially non-flexible shear knife 101 and 102,respectively, extends laterally across web 74 with the web 74 beingentirely unsupported on the lower face thereof which is opposed to upperface 79 and to the respective blades of each shear knife 101 and 102. Atypical shear knife is illustratively shown in FIG. 4b. For purposes ofthe apparatus shown in FIGS. 12a, 12b, and 12c, the knife shown in FIG.4b has a leading edge 250 and a trailing edge 260. Both to control theamount and type of shear force independently applied by each knife 101and 102 the web 74 passes over each knife edge in a contactingrelationship and three blade rolls 105, 106 and 107, that are providedin a typically fixed (but off-line adjustable) relationship relative toknives 101 and 102. The blades 101 and 102 are adjustable bothvertically and angularly. By adjusting the vertical height of each bladerelative to the web path, the force of each blade against the web can becontrolled. By adjusting the vertical height of the blade rolls, theshear force can be controlled and the angle at which the web contactsthe blades can also be controlled.

Relative to the direction of web 74 travel, blade rolls 105 and 106 thusare positioned so that roll 105 is on the lead side, and roll 106 on thetrailing side, of knife 101 while blade rolls 106 and 107 are positionedso that roll 106 is on the lead side, and roll 107 is on the trailingside of knife 102. The angle of inclination or tilt of each blade 101and 102 relative to the vertical is adjustable over a wide range, but itis presently preferred to adjust the blade inclination angle for eachblade between about ±45° relative to the vertical with the web 74 beinghorizontal. In the embodiment shown, each respective blade isfunctionally associated with a knife back support or holder 108 and 109,respectively. Each support 108 and 109 permits its associated blade 101and 102 to be vertically and angularly positioned relative to asupporting frame (not shown).

Another adjustable variable is the amount of angular web depressionwhich, in the embodiment shown, extends downwardly, achieved by the webin its passage over the circumferential edges of adjacent rolls 105 and106 relative to knife 101, and in its passage over the circumferentialedges of rolls 106 and 107 relative to knife 102. Considering the placewhere the knife 101 or knife 102 contacts the web to be a hypotheticalpoint, the angle of the knife 101 or knife 102 relative to the web canbe in the range of about 30° to about 140°.

While it is presently preferred to employ shear knives 101 and 102 whichhave straight edges to shear thin the polymer composition, it will beappreciated that shear knives having somewhat curved edges can be used,if desired. For example, when treating a web which displays differentiallongitudinal stretch characteristics laterally thereacross in responseto a uniform laterally applied warp tension, it appears to be possibleto equalize the shear forces applied to a web by employing a suitablycurved shear knife which appears to compensate for such a differentialstretch characteristic.

While it is presently preferred to employ shear knives 101 and 102 whichhave sharp edges, shear knives can also be used which have dull orrounded edges. It is also preferred to use knives having edges which aresurface finished to a uniformity of at least about root mean squared(RMS)8.

While it is presently preferred to employ shear knives 101 and 102 whichare formed of steel, other materials of knife construction could be usedif desired, such as metal alloys, non-metallic composites, and the like.The shear knives are preferably hardened or otherwise treated to reducewear.

Those skilled in the art will appreciate that the amount of shear forceapplied by one or more shear knives 101 or 102 transversely against aweb 74 is a function of many variables with probably the most importantor principal variables being the polymer viscosity, the longitudinal webtension, and the positioning of the shear knives 101 and 102 relative tothe web 74 during operation.

When a suitable and preferred level of applied shear force and webtensioning have been achieved to produce a product having encapsulatedor enveloped fibers and/or an internal coating, or both, one can usuallyhear a distinctive sound in the region of a shear blade 101 and 102.This sound can also be heard in the vicinity of shear blades being usedin the operation of other processes described herein. This sound can infact be used by an operator as a rough guide as to whether or not theoperator is succeeding in producing a product with controlled polymerplacement containing enveloped fibers and/or an internal coating, orboth.

Blade roll 105 also functions as a compensator roll for mechanicallyadjusting and controlling web tension before shear thinning begins.Also, conveniently and preferably the web tension is sensedelectronically, and then roll 105 is automatically raised or lowered toachieve web tensioning adjustments so as to maintain a presetpredetermined tension in web 74.

After passing over roll 107, the web 74 is passed over thecircumferential surface of a conventional padder roll 111. Between theblade roll 107 and the padder roll 111, a flexible so-called"flex-knife" or "Spanish knife" 100 is positioned. Preferably, the bladeof this flexible knife 100 is inclined at an angle with respect to theweb 74 passing thereagainst so that the knife 100 exerts a compressiveforce against the face 79 of web 74 with opposed face 103 being entirelyunsupported. The angle with respect to a (hypothetical) perpendicularline extending into a (hypothetical) straight line extending from thecircumferential edge of roll 107 to the circumferential edge of roll 111can range from about 30° to about 140° for the adjustment of theinclination angle of the flex knife. To provide adjustability forflexible knife 100, knife 100 is functionally associated with a mountingbracket or back support 113 which in turn is adjustable relative to anmethods and apparatus frame (not shown).

In the embodiment shown in FIG. 12a, the padder roll 111 is not employedas a web 74 treating means. It is not necessary to use the padder roll111 in all applications. It is typically only used when tension isneeded through the nip of the padder roll.

After leaving the mechanical tension compensator rolls 94, 95 and 96,web 74 is under reduced or preferably minimal tension and is led along apathway which extends over spacer rolls 113 and 114. Alternatively, theweb 74 may pass directly from the tension rolls 94, 95 and 96 into thecuring oven 119. In the region over spacer rolls 113 and 114, andgenerally between tension roll 96 and idler roll 117, a platform 116 isconveniently positioned which can incorporate suitable instrumentationpanels, operating controls and the like so that an operator can observethe operation of the apparatus in accordance with this invention andthen control and regulate the same. A position which is suitable foroperator observation of a web in progress that is located in thevicinity of a tenter frame 118 is desirable because it has been observedthat a web being processed can experience some distortion owing to theforces exerted thereon. These distortions can be metered and observedand then the tenter frame 118 adjusted by the operator so that, as theweb passes therethrough, the web can be straightened or shaped eitherlongitudinally or laterally, as desirable or considered necessary for anindividual web. If desired, the tenter frame 118 can be automaticallyoperated to apply tensioning forces to a web in accordance with apredetermined program, or the like. It is to be understood, however,that a tenter frame may not always be necessary or desirable. Many websmay be processed in accordance with the principles of this inventionwithout use of a tenter frame or other transverse tensioning device. Insuch cases, the web will pass directly into the curing ovens from thetension rolls 94, 95 and 96 or from the spacer rolls 113 and 114.

The tenter frame 118 also provides the start of a new zone of limitedlongitudinal and transverse tensioning which extends forwardly along theweb pathway from tenter frame 118 through oven 119 to a tensioncompensator, here shown as utilizing three tension rolls 121, 122 and123 which are part of a conventional mechanical tension compensatorsubassembly which is similar in structure and function to thecompensator subassembly incorporating the previously described tensionrolls 94, 95 and 96. The tensioning longitudinally of web 74 as itpasses through oven 119 is employed to control the web 74 as it passesthrough oven 119 as regards web dimensional limits. This tensioning ischosen to be at a level which does not introduce significant distortioninto the web, yet web sagging is avoided, as from thermal expansion andelongation. Rollers (not shown) can be used in the oven 119 to avoidsagging and to maintain uniform heat exposure. It has been found formany applications that it is desirable to cure the treated web undersubstantially no tension. It is preferable that the web be cured in arelaxed state so that its original construction or the physics of itsconstruction can be retained. This is instrumental for maintaining thecorrect hand and minimizing shrinkage.

In addition to serving as tension regulating means, the rolls 121, 122and 123 also serve to provide a cooling pathway for the web 74 as itemerges from the oven 119 before it passes over guide roller 124 andonto take-up roll 77.

The oven 119 functions to cure the polymer composition selectivelyplaced within the web 74. Oven 119 can be operated with gas or otherenergy source. Furthermore, the oven could utilize radiant heat,induction heat, convection, microwave energy or other suitable means foreffecting a cure which are known in the art. Oven 119 can extend forfrom about 12 to about 20 yards.

Curing temperatures of from about 320° to about 500° F., applied fortimes of from about 2 minutes to about 30 seconds (depending upon thetemperature and the polymer composition) are desirable. If a curingaccelerator is present in the polymer, curing temperatures can bedropped down to temperatures of about 265° F. or even lower (with timesremaining in the range indicated).

In place of an oven, or in combination with an oven, a source ofradiation can be employed (electron beams, ultraviolet light, or thelike) to accomplish curing, if desired.

Less than the full heating capacity of the oven 119 can be used, ifdesired. For example, only top heating or only bottom heating withrespect to the web can sometimes be used as compared to a combination ofboth top and bottom heating.

The take-up roll 77 is operating at approximately the same speed as thesupply roll 76. When the rotational speeds of take-up roll 77 are notsynchronized with rotational speeds of the supply roll 76, the tensionroll combination of rolls 121, 122 and 123 can be used to take up orreduce web slack, as the case may be.

Web transport speeds can vary widely; for example, from about 2 yardsper minute to about 90 yards per minute. Present speeds are from about35 yards per minute to about 50 yards per minute.

The apparatus and processes described above can be used in various formsor embodiments. Referring to FIGS. 12b and 12c, two alternate variationsor modes are seen. In such views, similar components are similarlynumbered but with the addition of single prime marks thereto in the caseof FIG. 12b and double prime marks thereto in the case of FIG. 12c.

In FIG. 12b, a further stage of web pressurization is introduced afterthe flex knife 112' and before the tenter frame 118'. Here, the web 74after passage through the flex knife 112' is passed through the nipregion 126 existing between padder roll 111' and associated transferroll 127 where the web 74' is subjected to compression between suchrolls 127 and 111' for the purpose of achieving a better distribution ofpolymer composition on web 74.

After leaving nip region 126, the web 74 is retained under somecompression against roll 127 by means of retaining bar or roll 128 forsimilar purposes. As discussed with reference to FIG. 12a, the web 74may pass directly into the oven 119' without utilizing the tenter frame118'. It is desirable that the web curing start promptly after tensionis released in the nip region 126, thus it is preferred that the nipregion 126 be located in close proximity to the entrance to oven 119'.

If desired, the roll 128 can be replaced by a flex knife (not shown)over whose edge the web 74' passes after departure from roll 127. Theflex knife can accomplish substantial further polymer distribution inweb 74.

Referring to FIG. 12c, there is seen an embodiment where the web 74 ispassed through the nip region of rolls 111" and 127". Here not only isuse of the mechanical tension roll combination having rolls 94, 95 and96 (as in FIG. 12a) eliminated, but also the rolls 111" and 127" serveto end the region of high longitudinal tension in the stages of blade orknife application to web 74 and to provide the desired reduced tensionfor web passage through a curing station, here illustrated by oven 119"which may or may not use the intervening tenter 118".

FIG. 14 depicts a schematic, side elevational view of a preferredembodiment or methods and apparatus for practicing the presentinvention. In this embodiment a continuous web 302 is moved undertension along a web pathway from a supply roll 301 to a take-up roll327.

The primary tension is a result of the differential rate between thedriven entrance pull stand designated as 306 and the driven exit pullstand designated as 322, whereby the exit pull stand 322 is driven at arate faster than the entrance pull stand 306. Other controllable factorswhich effect tension are the diameters of blade rolls 309, 314, 316,318; the vertical depth of blades 311, 315, 317; the durometer of theentrance pull stand rolls 304, 305 and rubber roll 321 of the exit pullstand, and the friction as the web passes under the blades.

Web 302 passes between the nip of the two rolls 304 and 305 of the entrypull stand 306. The entry nip is adjustable to produce a force of fromabout 100 lbs. to about 5 tons on the web, passing between the tworolls. The weight of top roll 305 provides an even distribution of forcethroughout the web width. Web 302 is flattened at this point and theinterstitial spaces are reduced laterally and longitudinally. Bottomroll 304 has micro-positioning capability to provide for gap adjustmentand alignment. The top roll 305 composition is chosen based on thedurometer of a urethane or rubber roll.

Web 302 continues to move along past idler roll 308 and blade roll 309and forms an entry angle α and an exit angle β with blade 311. Blade 311is illustratively shown in FIG. 4b. For purposes of the apparatus ofFIG. 14, the blade in FIG. 4b has a leading edge 250 and a trailing edge260. Entry angle α can be varied by adjusting: (a) the height anddiameter of blade rolls 309 and 314, (b) the horizontal position ofblade rolls 309 and 314,, (c) the angle of blade 311, and (d) the heightof blade 311. Similarly, the entry and exit angles of blades 315 and317, can be varied by adjusting the same devices surrounding each blade.

For illustrative purposes, increasing the height and diameter of bladeroll 309 decreases entry angle α. Rotating blade 311 clockwise, with web302 running left to right, increases entry angle α. Likewise, rotatingblade 311 counter-clockwise, with web 302 running left to right,decreases entry angle α. Decreasing the distance between blade roll 309and blade 311 decreases entry angle α. Increasing the downward depth ofblade 311 into web 302 decreases entry angle α.

The angle of blades 311, 315, and 317 are completely changeable andfully rotational to 360°. The fully rotational axis provides anopportunity for more than one blade per rotational axis. Therefore, asecond blade having a different thickness, bevel, shape, resonance,texture, or material can be mounted. Ideally the apparatus contains twoor three blades per blade mount. The blade mounts are not shown.

The force or pressure of blade 311 applied against web 302 is determinedby the vertical positioning of blade 311 in the blade mount. The greaterthe downward depth of blade 311, the greater the force or pressure.Blade pressure against the web is also accomplished through the tensionof the web as described above.

The same line components that affect entry angle α, also affect exitangle β. Any changes in the height, diameter, or horizontal positioningof blade rolls 309 and 314, affects exit angle β. If the angle of blade311 is rotated clockwise as described above, entry angle α increases,thus decreasing exit angle β.

As web 302 moves from left to right in FIG. 14, polymer is deposited onweb 302 with polymer applicator or dispersion means 310. Polymerapplicator 310 can be a pump, a hose, or any available applicationdevice for applying polymer onto the surface of the web. Polymerapplicator 310 is located directly in front of blade 311. The polymer isimmediately shear thinned, placed into, and extracted from web 302 bythe leading edge of blade 311, thus controlling the amount of polymerremaining in web 302. The bevel of blade 311 can effect entry angle αand the sharpness of the leading edge of blade 311. A sharper leadingedge has a greater ability to push the weave or structural elements ofweb 302 longitudinally and traversely, increasing the size of theinterstitial spaces. As the web passes the leading edge of blade 311,the interstitial spaces snap back or contract to their original size.

As web 302 moves from left to right in FIG. 14, the process of shearthinning and placing polymer into and extracting it out of web 302 isrepeated at subsequent blades 315 and 317, thus controllably placing thepolymer throughout web 302. Web 302 then passes over idler roll 319 andbetween driven exit pull stand 322 which consists of rolls 320 and 321.Pull roll 320 is a driven roll proportionally driven at a predeterminedrate slower than entry roll 304. Pull roll 321 does not apply pressureso much as it achieves a high degree of surface area in which web 302must come into contact with. The larger the surface area, the higher thedegree of contact friction. Pull roll 321 can be adjusted to havesufficient downward force to eliminate any slippage between web 302 andpull roll 320.

After web 302 passes from exit stand 322, it then moves into an oven 323for curing. Rolls 324, 325, and 326 provide a tension regulating meansand also serve to provide a cooling pathway for web 302 as it emergesfrom oven 323 before passing onto take-up roll 327.

The cure temperature of oven 323 is thermostatically controlled to apredetermined temperature for web 302 and the polymers used. Machineruns of new webs are first tested with hand pulls to determine adhesion,cure temperature, potentials of performance values, drapability,aesthetics, etc. The effect on web 302 depends on the temperature ofoven 323, dwell time and curing rate of the polymer. Web 302 may expandslightly from the heat.

Oven 323 functions to cure the polymer composition that is controllablyplaced into web 302. Oven 323 can be operated with gas or other energysources. Furthermore, oven 323 could utilize radiant heat, inductionheat, convection, microwave energy or other suitable means for effectinga cure. Oven 323 can extend from about 12 to 20 yards, with 15 yardslong being convenient.

Curing temperatures from about 320° F. to about 500° F., applied fortimes of from about two minutes to about thirty seconds (depending onthe temperature and the polymer composition) are desirable. If a curingaccelerator is present in the polymer, curing temperatures can bedropped down to temperatures of about 265° F. or even lower (with timesremaining in the range indicated).

The cure temperature of oven 323 and the source and type of cure energy,are controlled for a number of reasons. The cure temperature of oven 323is controlled to achieve the desired crosslinked state; either partialor full. The source and type of energy can also affect the placement ofthe polymer and additives. In place of an oven, or in combination withan oven, a source of radiation can be employed (electron beams,ultraviolet light, or the like) to accomplish curing, if desired. Forexample, by using a high degree of specific infrared and some convectionheat energy for cure, some additives can be staged to migrate and/orbloom to the polymer surfaces.

Oven cure dwell time is the duration of time the web is in oven 323.Oven cure dwell time is determined by the speed of the oven's conveyorand physical length of the oven. If the dwell time and temperature for aparticular web is at maximum, then the oven conveyor speed would dictatethe speed of the entire process line or the length of the oven wouldhave to be extended in order to increase the dwell time to assure properfinal curing of the web.

Take-up roll 327 is operated at approximately the same speed as supplyroll 301. When the rotational speeds of take-up roll 327 are notsynchronized with rotational speeds of supply roll 301, the tension rollcombination of rolls 324, 325, and 326 can be used to reduce web slack.

Web speed is proportional to the variable speed of the motor whichdrives entrance pull stand 306 and exit pull stand 322. Web speed caneffect the physics of the polymers as web 302 passes under blades 311,315, and 317. Web transport speeds can vary widely; for example, fromabout two yards per minute to about ninety yards per minute.

Typically, and preferably, webs of this invention are characterized byhaving fiber envelopment layers which range from about 0.01 to about 50microns.

A presently preferred web which is both fluorochemical and siliconepolymer treated and which is breathable, water resistant and rewashableis characterized as being a longitudinally tensionable porous flexiblefibrous web having opposed substantially parallel surfaces that arecomprised of associated fibers with interstices between the fibers, oris a matrix having cells or pores therein. The web is substantiallyuniformly impregnated with a fluorochemical and thereafter treated witha silicone polymer composition, to form a web having an internal layerwithin the web wherein the outer surfaces of the web are substantiallyfree of silicone polymer and the web is breathable and water resistantor waterproof. At least a portion of the fibers or cell walls areencapsulated or enveloped. At least one surface of the web ischaracterized by having a visual appearance which is substantially thesame as the visual appearance of one surface of the starting porous web.

When the web has fibers comprised of a synthetic polymer, the polymer ispreferably selected from the group consisting of polyamides, polyesters,polyolefins, regenerated cellulose, cellulose acetate, and mixturesthereof.

Preferred webs of this invention are more specifically characterized byhaving a water drop contact angle in the range of about 90° to about160°; a rewash capability of at least about 3; a breathability of atleast about 35% of untreated substrate web; and a water repellencyrating of at least about 80 prior to washing.

A general process for making a porous web of this invention comprisesthe steps of: tensioning a flexible, porous web as above characterized,applying a curable shear thinnable polymer composition to at least oneweb surface and then moving over and against one surface of thetensioned web a uniformly applied localized shear force to: shear thinthe polymer composition, uniformly place the composition within the web,at least partially individually encapsulate or envelop surface portionsof at least some of said fibers through the web matrix or position saidcomposition in a desired web internal region or some combination ofboth. Thereafter, the web is subjected to conditions sufficient to curethe composition in said web. Curing is accomplished by heat, byradiation, or both.

A presently preferred process for making a fluorochemical and siliconeresin treated web having breathability, water resistance andrewashability which is adapted for continuous operation comprises thesuccessive steps of: impregnating the web with a fluorochemical,longitudinally tensioning the fluorochemical impregnated web whilesequentially first applying to one surface thereof a curable siliconepolymer composition and concurrently applying a transversely exertedlocalized compressive force against said surface, and moving over saidsurface of the web substantially rigid shearing means which exertstransversely an applied, localized shear force against said surface toshear thin the polymer and wipe away exposed portions of siliconepolymer composition on said surface, thereby forming an internal layerof silicone polymer and/or enveloping at least some of the fibers orpassageways through the matrix, or both; and curing the silicone polymercomposition in the web.

The fluorochemical controlled placement operation is conveniently andpreferably carried out by the steps of: substantially completelysaturating the web with a solution or dispersion of a fluorochemicalcomposition in a carrier liquid; compressing the saturated web to removetherefrom excess portions of said dispersion; and heating said web toevaporate the carrier liquid therefrom. However, any convenient processcan be used for accomplishing fluorochemical pretreatment of a web to beused in this invention.

The following text concerns the theory of the invention as it is nowunderstood; however, there is no intent herein to be bound by suchtheory.

The presently preferred polymer composition used in the treatment ofwebs by this invention is a non-Newtonian liquid exhibiting thixotropic,pseudoplastic behavior. Such a liquid is temporarily lowered inviscosity by high pressure shear forces.

One aspect of the invention is a recognition that when high forces orsufficient energy are applied to curable polymer compositions, theviscosities of these materials can be greatly reduced. Conversely, whensubjected to curing, the same liquid composition sets to a solid formwhich can have a consistency comparable to that of a hard elastomericrubber. The internal and external rheological control of polymermaterials achieved by the present invention is believed to be of anextreme level, even for thixotropes. When subjected to shear force, thepolymer composition is shear thinned and can flow more readily, perhapscomparably, to water.

The invention preferably employs a combination of: (i) mechanicalpressure to shear thin and place a polymer composition into a porousweb; (ii) an optional porous web pretreatment with a water repellentchemical, such as a fluorochemical, which is theorized to reduce thesurface tension characteristics of the web and create a favorablesurface contact angle between the polymer composition and the treatedweb which subsequently allows, under pressure and shear force exertedupon an applied polymer composition, the production and creation of aninternal coating or layer which envelopes fibers or lines cell walls ina localized region within the web as a result of polymer flow in the webor which encapsulates the fibers within the web; and (iii) a polymercomposition impregnant preferably having favorable rheological andviscosity properties which responds to such working pressures andforces, and is controllably placed into, and distributed in a web. Thiscombination produces a web having the capability for a high degree ofperformance. This product is achieved through pressure controlledplacement and applied shear forces brought to bear upon a web so as tocause controlled movement and flow of a polymer composition into andthrough a web. Preferably, repeated compressive applications of pressureor successive applications of localized shear forces upon the polymer inthe web are employed.

By the preferred use of such combination, a relationship is establishedbetween the respective surface tensions of the polymer and the web,creating a specific contact angle. The polymer responds to a waterrepellent fluorochemical pretreatment of the substrate so as to permitenhanced flow characteristics of the polymer into the web. However, theboundary or edge of the polymer is moved, preferably repeatedly, inresponse to applied suitable forces into the interior region of a porousweb so as to cause thin films of the polymer to develop on the fibersurfaces and to be placed where desired in the web.

Thixotropic behavior is preferably built into a polymer used in theinvention by either polymer selection or design or additive/fillerdesign. For example, it now appears that thixotropic behavior can beaccentuated by introducing into a polymer composition certain additivesthat are believed to impart enhanced thixotropy to the resultingcomposition. A lower viscosity at high shear rates (during applicationto a web) is believed to facilitate polymer flow and application to aweb, whereas a polymer with high viscosity, or applied at a low shearrate (before and/or after application) actually may retard or preventstructural element (including fiber) envelopment or encapsulation.

Illustratively, the practice of this invention can be considered tooccur in stages:

In stage 1, a silicone polymer composition impregnant is prepared. Itcan be purchased commercially and comes in typically two partsdesignated as A and B. For example, in a silicone polymer composition,as taught in U.S. Pat. No. 4,472,470, a base vinyl terminatedpolysiloxane is the A part, while a liquid organohydrogensiloxanecontrolled crosslinking agent is the B part. Certain remainingcomponents, such as a resinous organopolysiloxane copolymer and aplatinum catalyst may (or can) apparently initially be in either part Aor part B.

Stage 2 can be considered to involve the mixing of such a product'sparts with or without additives. Changes in viscosity can be obtainedand measured based on applied shear rates and shear stresses. Suchchanges can be experienced by a polymer with or without additives. Up toa 99% reduction in viscosity of a liquid silicone polymer composition isbelieved to be obtainable by the shear forces involved in the shearthinning and forcing of a silicone polymer composition impregnant into aweb. Thereafter, a very substantial increase in polymer viscosity isbelieved to be obtainable taking into account these same factors.Normally, the most significant factor is now believed to be the sheargradient that typically reduces the viscosity of the polymer below thestarting or rest viscosity.

Stage 3 can be considered to be the pressure introduction stage. Up to a99% reduction of the polymer viscosity is believed to be obtainable dueto the applied shear forces, elapsed time, temperature, radiation and/orchemical changes. Thereafter, a significant increase or even more in theresulting polymer viscosity is believed to be obtainable. In this stage,partial curing of the polymer may take place. Most commonly, polymerviscosity is substantially decreased during the pressure controlledplacement Stage 3 by the application of shear forces.

Stage 4 can be considered to be the first stage internal matrixdispersing and reintroduction with metering, and also recovery andrecycle of excess polymer. Typically, within this Stage 4, the shearforces cause a substantial but temporary lowering of polymer viscosity,causing it to flow upon and into the three-dimensional structure of theweb. The initial viscoelastic character of the polymer is typicallytheorized to be recovered almost immediately after shear forces areremoved.

Stage 5 can be considered to be a second stage internal matrixdispersing and reintroduction with metering and also recovery andrecycling of excess polymer. The variations in the viscosity of thepolymer are equivalent to Stage 4. The viscosity of the polymer is againlowered causing it to flow within the web. Because of the application ofrepeated shear force induced reductions in viscosity, the thixotropicbehavior of a polymer may not undergo complete recovery, following eachapplication of shear force and the viscosity of the polymer may notrevert to its original placement values. The polymer composition isbelieved to have the capacity to form enveloping internal coating in apredetermined region wherein the interstices or open cells aresubstantially completely filled within the three-dimensional matrixconstituting a web during the time intervals that the is caused to flowunder pressure in and about matrix components. In between these times,the polymer may recover substantially all of its initial high viscosity,although perhaps slightly less so with each repeated application ofshearing pressure or force.

Stage 6 can be considered to be occurring just as curing is begun, andjust as heat is introduced.

Stage 7 can be considered to be occurring with regard to the exertion ofcontrol of curing. Typically, at least a partial curing (includingcontrolled cross-linking and/or polymerizing) is obtained by relativelylow temperatures applied for relatively short times. For example, whenlight cotton, nylon, or similar fabrics are being treated, temperaturesunder about 350°, applied for under about 10 seconds, result in partialcuring.

FIG. 8, consisting of FIGS. 8a through 8d, shows four graphsillustrating four ways that could be used for plotting polymerrheological behavior: (a) shear rate versus shear stress (uniformscales), (b) shear rate versus shear stress (log scales), (c) viscosityversus shear rate (uniform scales), and (d) viscosity versus shear rate(log scales), if desired, in the practice of this invention. Only thelog versus log scales are believed to be capable of encompassing a fullrange of values for the three indicated variables. The graphs representsome broad ranges of viscosity changes relative to shear stress thatcould be undergone by a given silicone polymer composition duringexecution of a given pressured controlled placement procedure as taughtherein.

For the purposes of the present invention, the term "surface tension"can be considered to have reference to a single factor consisting ofsuch variables as intermolecular, or secondary, bonding forces, such aspermanent dipole forces, induced forces, dispersion or nonpolar van derWaals forces, and hydrogen bonding forces. The strong primary bondingforces at an interface due to a chemical reaction are theorized to beexcluded from surface tension effects; however, it is noted that even asmall degree of chemical reactivity can have a tremendous influence onwetting effects and behavior affected by surface tension.

Surface tension is believed to induce wetting effects which caninfluence the behavior of a polymer composition impregnant relative tothe formation of either a fiber enveloped layer therewith in a fibrousporous web, fiber encapsulation or both. For example, adhesion istheorized to be a wetting effect. Spontaneous adhesion always occurs forcontact angles less than about 90°. However, for a combination of arough surface and a contact angle over 90°, adhesion may or may notoccur. In fact, roughness becomes antagonistic to adhesion, and adhesionbecomes less probable as roughness increases.

Also, penetration is theorized to be a wetting effect. Spontaneouspenetration occurs for contact angles less than about 90°, and does notoccur for contact angles over about 90°. The roughness of a solidsurface accentuates either the penetration or the repellency action, buthas no influence on which type of wetting takes place.

In addition, spreading is theorized to be a wetting effect. Retractionoccurs for contact angles over 90° or over planar surfaces for anycontact angle. However, spontaneous spreading for contact angles lessthan 90°, especially for small contact angles, may be induced by surfaceroughness.

FIG. 9 is a schematic vector diagram illustrating the surface tensionforces acting at the vertex boundary line of a liquid contact angle on aplanar solid surface. It illustrates how surface tension forces might bemeasured between a silicone polymer composition and a fiber of a web (ora fabric) as treated by the invention.

FIG. 10 is a graph relating the contact angle over a smooth solidsurface as a function of θ and i that apply respectively, to adhesion (Icos θ+1), penetration (i cos θ), and spreading (i cos θ-1).

Regions of adhesion versus abhesion, penetration versus repellency, andspreading versus retraction are shown by shaded areas. FIG. 10illustrates what is theorized to be the relationship of a siliconepolymer composition to silicone polymer composition solids in a treatedweb as regards such factors as adhesion, penetration, spreading, andretraction.

FIG. 11, consisting of FIGS. 11a through 11d, shows representativeviscosity profiles plotted on log viscosity versus log shear rate graphsfor (a) pseudoplastic flow, (b) dilatant flow, (c) pseudoplastic flowwith superimposed thixotropic behavior, and (d) laminar Newtonian flowthat erupts into turbulent flow at a critical transition point.

FIGS. 11a through 11d show a broad range of illustrative flowcharacteristics that could be demonstrated by silicone polymercomposition impregnants suitable for use in this invention usingpressured controlled placement of a web as taught herein.

For purposes of this invention, the term "wetting" is used to designatesuch processes as adhesion, penetration, spreading, and cohesion. Ifwetting transpires as a spontaneous process, then adhesion andpenetration are assured when the solid surface tension exceeds theliquid surface tension. Surface roughness promotes these spontaneouswetting actions. On the other hand, no such generalizations can be madewhen the solid surface tension is less than the liquid surface tension.

Surface tension is measured as by S.T.L. units for liquid and by S.T.S.units for solids; both units are dyns/centimeter. When S.T.S. is lessthan S.T.L., then wetting is less ubiquitous and prediction of wettingbehavior is more difficult. However, by taking advantage of theliquid/solid contact angle that forms when a liquid retracts over asolid, it is possible to calculate with reasonable accuracy the wettingbehavior that can be expected. The reduction in liquid surface area canbe computed in terms of the contact angle that the liquid makes with thesolid surface. Contact angles are always measured in the liquid phase.There is a point of equilibrium where the surface tension forces becomebalanced.

By measuring the contact angle of a liquid on a solid, the wettingbehavior of the liquid impregnant can be measured.

This invention is further illustrated by the following examples, whichare not to be construed in any way as imposing limitations upon thescope thereof. On the contrary, it is to be clearly understood thatresort may be had to various other embodiments, modifications, andequivalents thereof, which, after reading the description herein, maysuggest themselves to those skilled in the art without departing fromthe spirit of the present invention and/or the scope of the appendedclaims.

EXAMPLES Example 1 Liquid Silicone Polymer Preparation

100 parts by weight of the curable liquid silicone polymer availablecommercially from Mobay as "Silopren® LSR 2530" was mixed in a 1:1ratio, as recommended by the manufacturer. A Hockmayer F dispersionblade at low torque and high shear was used to do the mixing. To thismixture were added 5 parts by weight of BSF "Uvinul 400" and 5/10 partsby weight Dow Corning 7127 accelerator, believed to be a polysiloxanebut containing an undisclosed active accelerated ingredient.

Examples 2-19 Liquid Silicone Polymer Preparation

The procedure of Example 1 was repeated with various other curableviscous liquid silicone polymer compositions commercially available. Tothis product system is added a substituted benzophenone and otheradditives, the result of which are shown in Table II. All parts are byweight.

                                      TABLE II    __________________________________________________________________________                                      SUBSTITUTED    EXAMPLE             MIXTURE RATIO OF                                      BENZOPHENONE                                                OTHER ADDITIVES    NO.   STARTING SILICONE RESIN                        PACKAGED COMPONENTS.sup.(1)                                      NAME  PARTS                                                NAME           PARTS    __________________________________________________________________________    1     Silicoren ® LSR 2530                        1:1           Uvinul 400                                            5   2127 Accelerator                                                               5/10    2     Silastic ® 595 LSR                        1:1           Uvinul 400                                            5   Syl-Off ® 7611.sup.(2)                                                               50    3     SLE 5100      10:1          Uvinul 400                                            5   Sylox ® .sup.(3)                                                               80          Liquid BC-10  1:1    4     Silopren ® LSR 2530                        1:1           Uvinul 400                                            5   Hydral ® 710.sup.(4)                                                               10    5     Silopren ® LSR 2530                        1:1           Uvinul 400                                            5   Silopren ® LSR                                                Z3042.sup.(5)  1    6     SLE 5500      10:1          Uvinul 400                                            5    7     Silopren ® LSR 2540                        1:1           Uvinul 400                                            5    8     SLE 5300      10:1          Uvinul 400                                            5    9     SLE 5106      10:1          Uvinul 400                                            5    10    Silopren ® LSR 2530                        1:1           Uvinul 400                                            5   Flattening Agent OK412                                                ®.sup.(6)  4    11    Silopren ® LSR 2530                        1:1           Uvinul 400                                            5   Nalco ®  ISI-612                                                Colloidal Silica.sup.(7)                                                               50    12    Silopren ® LSR 2530                        1:1           Uvinul 400                                            5   Nalco ® ISI-614 Colloidal                                                Alumina.sup.(8)    13    Silastic ® 595 LSR                        1:1           Uvinul 400                                            5   200 Fluid.sup.(9)                                                               7    14    Silopren ® LSR 2530                        1:1           Uvinul 400                                            5    15    Silastic ® 595 LSR                        1:1           Uvinul 400                                            5   Zepel ® 7040.sup.(10)                                                               3    16    Silastic ® 595 LSR                        1:1           Uvinul 400                                            5   Zonyl ® UR.sup.(11)                                                               1/10    17    Silastic ® 595 LSR                        1:1           Uvinul 400                                            5   Zonyl ® PSN-100.sup.(12)                                                               1/10    18    Silopren ® LSR 2530                        1:1           Uvinul 400                                            5   DLX-600 ®.sup.(13)                                                               5    19    Silopren ® LSR 2530                        1:1           Uvinul 400                                            5   TE-3608 ®.sup.(14)                                                               5    __________________________________________________________________________     TABLE II Footnotes:     .sup.(1) Ratio listed is that recommended by the manufacturer.     .sup.(2) Syloff ® (registered trademark of Dow Corning) is a     crosslinker.     .sup.(3) Sylox ® 2 (registered trademark of W.R. Grace Co.) is a     synthetic amorphous silica.     .sup.(4) Hydral ® 710 (registered trademark of Alcoa) is hydrated     aluminum oxide.     .sup.(5) Silopren ®LSR Z/3042 (registered trademark of Mobay) is a     silicone polmer (bonding agent) mixture.     .sup.(6) Flattening Agent CK412 ® (registered trademark of Degussa     Corp.) is a wll coated silicon dioxide.     .sup.(7) Nalco ® ISI612 Colloidal Silica (registered trademark of     Nalco Chemical Company) is an aqueous solution of silica and alumina.     .sup.(8) Nalco ® ISI614 Colloidal Aluminum (registered trademark of     Nalco Chemical Company) is an aqueous colloidal aluminum dispension.     .sup.(9) 200 Fluid (registered trademark of Dow Corning) is a 100     centistoke viscosity dimethylpolysiloxane.     .sup.(10) Zepal ® 7040 (registered trademark of duPont) is a monomic     fluoropolymer.     .sup.(11) Zonyl ® UR (registered trademark of duPont) is an amionic     fluorosurfactant.     .sup.(12) Zonyl ® RSN100 (registered trademark of duPont) is a     monimonic fluorosurfactant.     .sup.(13) DLX6000 ® (registered trademark of duPont) is     polytetrafluoroethylene micropowder.     .sup.(14) TE3608 ® (registered trademark of duPont) is a     polytetrafluoroethylene micropowder.

Example 20 Internally Coated Fiber Encapsulated. Interstice FilledFabric Preparation

A complete, stepwise, application of the inventive method in theproduction of an encapsulated fiber fabric was as follows.

The selected base fabric was TACTEL® (gold color) #612071 available fromICI Americas, Inc. through their agent, Arthur Kahn, Inc. This fabricwas 100% woven nylon. If desired, this and other fabrics may becalendered to modify surface texture. The fabric was weighed andmeasured. Its initial weight is 3.1 ounces per square yard. Itsthickness equals 9 mils. The fabric was next washed with detergent,rinsed thoroughly, and hung to air dry. The fabric was soaked in water,wrung dry, and weighed. The water retained was equal to 0.8 g water/gfabric. The fabric was then treated with a water repellentfluorochemical, a 2% solution by weight of Zepel® 7040. In order to doso the fabric must be soaked in a 2.5% solution of Zepel®water-repellent chemical in distilled water. This was because: ##EQU2##The treated fabric was then run through a wringer and air dried. Next,the fabric was heated in an oven for 1 minute at 350°. This heatingsinters the water repellent fluorochemical. The fabric with itsfluorochemical residue is then run as in the FIG. 7 embodiment, in avertical configuration and is described below. The fabric is run from aroll that incorporates significant braking or clutching to initiate thetension required for controlled material alignment and coating duringapplication. The fabric web travels through a series of idler rollsending at the application trough. As it passes the application trough,it picks up a thin coating of silicone impregnant and then moves under ashear blade that is parallel to the floor. The silicone impregnant isapplied at 1.0 oz./sq. yd. and continues under a flex blade that is alsoparallel to the floor.

Multiple process stages of running the fabric with applied impregnantunder the blades are preferably made. The multiple process stages areimportant, and are normally necessary. The impregnant is Mobay 2530 A/Bin a 1:1 ratio and can be considered to be a viscoelastic liquid thatflows only under the shear forces resulting from the pressuredcontrolled placement. The impregnant is believed to return verysubstantially to its original viscous condition almost immediately uponrelease of the pressure. The impregnant was believed to flow a shortdistance within the matrix of the fabric during the short time that itwas, because of pressure shearing forces, of lowered viscosity.Therefore, a number of "flows" may be usefully generated in a number ofpasses in order to properly distribute the impregnant in its preferredposition substantially encapsulating the surfaces of the fabric'sfibers.

Finally, the impregnated fabric was run through a line oven, ofapproximately 10 yards in length, at 4-6 yards per minute, and was curedat 325°-350° F. It then passes through a series of idler rollers and isrolled up on a take-up roll, completing the tension zone. The resultantfabric has a non-tacky thin film of silicone that was internally coatedto form a fiber encapsulated, interstice-filled layer in the fabric.

Example 21 Evaluation of Fiber Encapsulated Fabric Properties

The test results of the original versus the produced fiber encapsulatedfabric of Example 20 were as follows:

                  TABLE III    ______________________________________    FABRIC        ORIGINAL FABRIC                                ENCAPSULATED    ______________________________________    Spray Rating (1)                  20            100 (reverse = 100)    Rain Test (2) Fail          Pass    Abrasion Test (cycles) (3)                  1,800         3,200    Moisture Penetration (4)                  Saturated     0.0 g    Hydrostatic Resistance                  1             2    (psi) (5)    MVTR (g/M.sup.2 /day)* (6)                  4,414         2,362    Weight (oz/yd.sup.2)                  3.1           4.1    ______________________________________     Amount Impregnated = 1.4 oz/yd.sup.2     *Environmental chamber at 104° F. and 74% humidity.

                  TABLE IV    ______________________________________    LAUNDERING TEST  TIMES WASHED    (Spray Ratings)  Initial                            5X       10X  15X    ______________________________________    Impregnated Side 100    90       90   90    Reverse Side     100    90       90   90    Unimpregnated Treated Fabric                     100    80       80   40    ______________________________________     Accelerated Weathering Test (8)     Samples placed in QUV weatherometer for 72 hours.     Original = 7     Impregnated Side = 9     Reverse Side = 8

(1) The spray test was conducted in accordance with AATCC 22-1974. Itmeasures water repellency of a fabric sample on a scale of 0-100, with areading of 100 designating a completely water repellent fabric.

(2) The rain test was conducted in accordance with AATCC 35-1985. Itmeasures resistance of a fabric sample to penetration of water understatic pressure from a shower head of 3 feet/5 minutes. A fabric isstormproof when less than 1.0 gram of water is absorbed by astandardized blotter used in the test.

(3) The abrasion test was conducted in accordance with Federal TestMethod Standard 191 A, Method 5306. Abrasion resistance is measured bymounting a fabric sample on a Taber Abraser Model 174 and measuring thenumber of cycles before the fabric begins tearing apart.

(4) The hydrostatic resistance test was conducted in accord with FederalTest Method Standard 191A, Method 5512. The test measures a fabricsamples' resistance to water under pressure using the Mullen's BurstTest methods and apparatus. Test results are expressed in pounds persquare inch at which water beads penetrate the fabric.

(5) The moisture vapor transmission (MVTR) test was conducted inaccordance with ASTM E96-B. The test measures the amount of moisturevapor passing through a fabric sample in a controlled environment duringa 24 hour period. The obtained MVTR figure is expressed in grams ofwater/square meter of surface/24 hour day. The environmental chamber washeld at 104° F. and 47% humidity.

(6) The moisture vapor transmission (MVTR) test was conducted inaccordance with ASTM E96-B. The test measures the amount of moisturevapor passing through a fabric sample in a controlled environment duringa 24 hour period. The obtained MVTR figure is expressed in grams ofwater/square meter of surface/24 hour day. The environmental chamber washeld at 104° F. and 478 humidity.

(7) A laundering test of the conventional household type was performed.Fabric samples were washed with Tide® detergent. There was no drying. Aspray test was subsequently carried out after each wash to determine theeffect of the washing.

(8) The accelerated weathering test was conducted in accordance withASTM G-53. Samples of original and impregnated fabrics were placed inthe weatherometer of QUV Company and results were compared. (Allreadings were based on a graduated color scale of 0-20; 10 designatedthe original color, while 0 designated a white out.)

Example 22 Description of Fabric Controlled Placement Through ScanningElectron Microscope (SEM) Photomicrographs

FIGS. 3a, 3b and 3c were taken using a Cambridge 360 scanning electronmicroscope. The samples were cut using Teflon coated razor blades,mounted on 1/2 inch diameter aluminum stubs and coated with agold/palladium alloy.

FIG. 3a is a photomicrograph of the gold color Tactel fabric describedin Example 20. The surface of the material has been magnified 120 timesand shows that the cured silicone polymer impregnant is present as athin film, or coating, or layer within the material and envelopes atleast a portion of the fibers. The fiber bundles are somewhatdistinguishable in the weave, but each filament in the fiber bundles isnot individually distinct.

The sample in FIG. 3b has been magnified 600 times and shows thecross-section of a fiber bundle from the same Gold Tactel in FIG. 3a.The cured silicone polymer impregnant envelopes at least a portion ofthe fibers. The interstices or void areas between filaments in theregion of the internal coating are mostly filled or plugged by suchimpregnant. However, the web remains breathable and because of theimpregnant barrier, is either water resistant or waterproof.

FIG. 3c is the side of the fabric in FIG. 1 opposite from which thesilicone polymer impregnant was applied. The silicone polymer impregnantis most readily apparent at the fiber bundle interstices and not visiblein the fiber bundles themselves.

Example 23 Fiber Enveloped Fabric Preparation

The selected base fabric was Arthur Kahn TACTEL® (hot coral) #70146.This fabric is 100% nylon. The fabric was pretreated at Cal-Pacific (acommercial finisher of fabrics) with duPont ZEPEL® 6700. The impregnantcomposition is Mobay LSR 2530 A/B in a 1:1 ratio=5% W UVINUL® 400 (5% oftotal weight of Mobay LSR). Controlled placement of this composition wasperformed in a three stage continuous process using equipment as shownin FIG. 7 consisting of the following procedure:

The composition was applied to the fabric at (a) a pressure of 3lbs./linear inch, utilizing (b) a shear (bar) knife at a high pressure,and at a 90° angle to the fabric (the edge of the knife is milledsharp). The rate of application is at approximately 1.0 oz./sq. yd. Aflex knife was then applied at a 45° angle with the recovery systemutilizing gravity. For both (a) and (b) above, the microweb pressure wasapplied at a low web speed on a roller system varied at from about260-400 yards per hour. Next, the fabric is cured using an upper oven(lower oven turned off) at a temperature of about 320°-330° F. Thefabric was in the oven for approximately 3 to 4 minutes. The impregnantcures to a non-tacky thin film, as in the previous example.

Example 24 Prior Art Silicone Polymer Treated Fabric

The fabric resulting from a prior art application of a viscous liquidcurable silicone polymer composition is shown in FIG. 2. Thephotographic view of FIG. 2 is at 150X magnification. It shows apolyester and cotton cloth blend into which Dow Corning 590 LSR siliconepolymer composition has been coated by a procedure of the prior art. Thefabric side shown in FIG. 2 is the top, or treatment, side, which wasthe fabric side upon which coating was accomplished.

As shown by the example of the treated fabric of FIG. 2, the prior artimpregnated fabric is characterized by a high degree of disorder. Alarge number of particulates (typical) appear to litter the surface ofthe fabric. A substantial portion of the area of the surface, whichappears to be a solid layer, is silicone polymer composition. Certainyarn fragments can be observed to protrude through the surface of thissilicone polymer composition. Additionally, the silicone polymercomposition on either the polyester or the cotton fibers, is not anencapsulation layer, but rather a matrix with the coated fibers being ingeneral disarray, probably from forces occurring during the indicatedprior art silicone polymer composition application procedure. Althoughsilicone polymer composition is present upon the yarn or fiber surfacesof the substrate, and certainly is present as a layer upon the exteriorsurface of the three-dimensional fabric body, the silicone polymercomposition has not controllably and individually encapsulated thefibers and left the interstices between fibers largely devoid of suchpolymer. In the prior art, a placement of silicone polymer compositionin a fabric is not controlled to such a degree so as to produce aproduct in accordance with the present invention.

Example 25 Description of Fabric Controlled Placement Through ScanningElectron Microscope (SEM) Photomicrographs

FIGS. 13a, 13b and 13c were taken using a Cambridge 360 scanningelectron microscope. The samples are cut using Teflon coated razorblades, mounted on 1/2 inch diameter aluminum stubs, and coated with agold/palladium alloy.

FIG. 13a is a photomicrograph of the Tactel (Hot Coral) fabric describedin Example 23. The surface of the material has been magnified 120 timesand shows that the cured silicone polymer impregnant is present as athin film, or coating, or layer within the material and envelopes atleast a portion of the fibers. The fiber bundles are somewhatdistinguishable in the weave, but each filament in the fiber bundles isnot individually distinct.

The sample in FIG. 13b has been magnified 800 times and shows thecross-section of a fiber bundle from the same Tactel in FIG. 13a. Thecured silicone polymer impregnant envelopes at least a portion of thefibers. The interstices or void areas between filaments in the region ofthe internal coating are mostly filled or plugged by such impregnant.However, the web remains breathable and because of the impregnantbarrier is either water resistant or waterproof.

FIG. 13c is the side of the fabric in FIG. 1 opposite from which thesilicone polymer impregnant was applied. The silicone polymer impregnantis most readily apparent at the fiber bundle interstices and not visiblein the fiber bundles themselves.

FIG. 15a depicts a 330 denier cordura fiber, encapsulated with acomposite polymer, magnified 1950 times. The left side of the picture isin normal scanning electron mode and the right side of the picture ismagnified 10 times in secondary electron microscopy back scatter mode.The isolated rectangular box image in the middle of the left side wasexposed to destructive electron beams isolated on the central opening inthe center of the wrinkled formation. The wrinkled film casingrepresents the composite polymer (solid silicone and oxyethylated nylon)thin-film, this is a direct result of the destructive electron exposure.The image on the left side of the picture has surrounding fibers on theleft and right side of the isolated fiber, which also has some wrinkledeffects on the thin-film as a direct result of the destructive electronanalysis. The rectangular box on the upper side of the picture wastargeted for an elemental analysis. The electron beam was targeted atthe rectangular box with very low current (10 KV and probe at 3.0 nA) toinsure isolation of elemental signal from any other area. FIG. 15bdepicts the elemental graph of the targeted region, which clearly showsthe presence of the composite polymer containing si or silicon.Combined, FIGS. 15a and 15b show fiber encapsulation by the compositepolymer.

FIG. 15c depicts a cut end of a filament illustrating a thin filmencapsulation in white. A crack was created in the filament with a hightemperature electron beam. This crack continues under the surface of thethin film. The filament has been cut and the thin film has beenstretched or elasticized by the cutting of the filament. The two arrowsin the upper right corner show the thickness or distance represented bythe black box in the lower right corner as 126 nm.

FIG. 15d depicts an isolated image on 330 Denier Cordura single filamentfiber processed with the micro-finish fiber coating technology,magnified 5,720 times. The Bioengineered Comfort™ polymer containingengineered protein and solid silicone was used in the process with amoderate degree of shear. The image on top of the fiber is anundispensed protein polymer which clearly illustrates the presence ofthe protein after the micro-finish fiber coating process. The surfacemorphology has very small protein polymer particles encapsulated in thesolid silicone polymer and is homogeneously dispersed throughout thefilm system on the fiber.

FIG. 15e is an image of a white nylon magnified 178 times. Theapplication side is shown at the bottom left hand corner of the image.The upper portion of the image is the non-application side. At the upperright corner is the intersection of the warp and fill fiber bundles,where the polymer presence can clearly be seen on the fibers. Theinternal layer of polymer that creates the liquid barrier or resistantproperty can be seen along the bottom right corner of the picture. Thisinternal layer is a combination of polymer filling some interstitialspaces and polymer "glueing" together the fibers and filaments of theweb.

FIG. 15f is a Tunneling Electron Microscopy (TEM) image of a thin crosssection of a filament encapsulated with polymer. The lighter image onthe lower side of the frame is a polyester filament. The black sphericaldots on the outer edge of the fiber are extremely dense processedmaterial. In this imaging technique, the darker the image, the denserthat specific material.

FIG. 15g depicts an individual filament shown in a split screen format.The left hand image is showing the filament with submicron metalparticles dispersed in the processed film. The right hand portion of thesplit screen is imaging the filament with a technique known as secondaryelectron back scattering. The bright particles are the same particles onthe same fiber as seen in the left side of the split screen. Thedifference is one of density, the brighter metal particles are imagingdensity differential over the underlying filament.

FIG. 15h depicts a nylon fabric magnified 419 times with bright particletracer images and a cross sectional image of a nylon fabric. Thesebright particles are submicron metal particles dispersed throughout thefabric in the processed film. The addition of bright copper submicronparticles in the polymer allows secondary back scatter mode toillustrate the complete encapsulation ability of the controlledplacement technology. The left side of the image is the performance sideof the fabric which is the non-application side of the polymer, but itis clear, with the presence of the glowing brightness of the coppersubmicron particles throughout the performance side of the fabric, thatcontrolled placement technology successfully encapsulates completelyaround the fibers throughout the fabric structure. The other clearunique feature of the controlled placement technology is that each fiberis still independent. This differentiation allows the controlledplacement technology's processed fabrics to retain exceptional hand andtactile quality, while still imparting performance characteristics. Onthe left side of the fabric, directly underneath the printed text"performance side", an elemental analysis was conducted and the outcomeof that analysis is depicted in FIG. 15i. The result clearly shows astrong presence of submicron copper particles.

In the next examples that involve accelerated weathering, abrasion,water repellency, moisture penetration, and rain testing, data isprovided for a Tactel fabric identified as Deva Blue. The fabric is 100%nylon, available from Arthur Kahn and identical in composition,preparation, and enveloping specification to that of the Hot Coralpresented in previous examples.

Example 26 Accelerated Weathering Test

The results of weathering upon a treated web of this invention are shownin actual tested sample pieces comparing original fabrics withembodiments of the enveloped fiber fabrics of this invention.

In every case, the enveloped fiber fabric samples were found to havesignificantly better weathering characteristics than the originaluntreated fabrics as determined by accelerated weathering tests. Eventhe reverse side (compared to the treated side) of an enveloped fibernylon fabric of the Tactel® type was improved over the original fabric.In addition, the excellent "hand" of the enveloped fiber fabric wasfound to have been maintained after the accelerated weathering test.

The test performed conforms to each of the following performancestandards:

ASTM G-53 light/water exposure materials

ASTM D-4329 light/water exposure-plastics

General Motors Test spec TM-58-10

ISO 4892 Plastics exposure to lab light

The procedure used for the accelerated weathering testing involvedsubjecting fabric samples to four hours of high-intensity ultravioletlight, alternating continuously with four hours of water condensation,wetting the fabric in the dark. This alternating exposure (four hourson, four hours off) to high-intensity ultraviolet light and waterwetting, simulates outdoor environmental conditions in a vastlyaccelerated manner, quickly degrading unprotected dyes and fibers. Themethods and apparatus used for this test was a QUV AcceleratedWeathering Tester from The Q-Panel Company, 26200 First Street,Cleveland, Ohio 44145.

The results obtained on some sample fabrics are expressed in Table V. Inthis Table, results are expressed in the form of "A/B" where A and B arenumbers. The number "A" is the color rating on a graduated scale from 0to 10. The number 10 equals perfect (original) condition where 0 equalsa white color and a completely faded fabric. The number "B" is thenumber of hours of weathering transpiring when the number "A" rating wasobtained.

                                      TABLE V    __________________________________________________________________________    Accelerated Weathering Testing                                      COLOR RATING                                      (RATING/HOURS)                        ENVELOPED                               REVERSE                                      10 - PERFECT              ORIGINAL FABRIC                        FABRIC SIDE   0 = WHITE COLOR    ORIGINAL FABRIC              WEATHERED WEATHERED                               WEATHERED                                      FADES OUT    __________________________________________________________________________    TACTEL° Deva Blue              3/159     8/159         After 159 hrs.,    9-420-6-1                         enveloped fabric    10/0                              significantly less                                      weathered than                                      original; original                                      nearly white;                                      enveloped fabric still                                      light blue.    TACTEL° Hot Coral              5/24      10/24  9/24   After 24 hrs.    9-420-6-2 (AKA 18)                enveloped fabric is    10/0                              significantly less                                      weathered than                                      original, as was                                      reverse side.    __________________________________________________________________________

Example 27 Abrasion Resistance Testing

The results of abrasion resisting testing clearly show that envelopedfiber fabrics of this invention have superior wear characteristicscompared to the untreated original (starting) fabrics. In most cases,the enveloped fiber fabric samples underwent twice as many cycles as theuntreated samples without evidencing tearing in the samples. Suchresults can be explained by theorizing that the envelopment withsilicone polymer of the yarns and fibers comprising a fabric, providessuch treated yarns and fibers with a lubricity agent so that abrasiveaction was minimized and the integrity of the fabric was preservedsignificantly longer. The anti-abrasion characteristics also applied tothe minimized effects of one fiber rubbing against another fiber, or ofone yarn against another yarn.

This experiment compared the abrasion resistance of embodiments of theenveloped fiber fabrics of this invention with untreated fabrics. Thedurability of each fabric test specimen was determined by the TaberAbraser. Each specimen is abraded for the number of cycles indicated.Comparisons were then made between the enveloped fiber fabrics of theinvention and untreated fabrics. Specifically, this test method utilizesthe Taber Abraser No. 174. An important feature of this abrader was thatits wheels traverse a complete circle on the test specimen surface.Thus, the surface was abraded at all possible angles relative to theweave or grain of the specimen. Comparisons of the enveloped fiberfabric to the untreated fabric were based upon a scale 0 through 10,where 0 was a completely torn specimen, and 10 was the new (or starting)sample.

Each test procedure used a single 7 inch diameter fiber enveloped fabricspecimen, and a single 7 inch diameter original (untreated) fabricspecimen. The procedure used was as follows:

1. A test specimen of the fiber enveloped fabric with a 7 inch diameterwas cut.

2. An equally-sized specimen of control (untreated) fabric was cut.

3. The fabric specimen was mounted on the rotating wheel securely andthe clamps were screwed down.

4. The counter was set.

5. The vacuum power adjustment was set. (For this experiment, vacuum wasset at 80.)

6. The abraser was started.

7. At the procedurally specified number of revolutions, the abraser wasstopped and each fabric sample was rated at a value between 0 and 10.

Illustrative results of the test on some sample fabrics are shown inTable VI.

Abrasion Testing Numeric Grade of Abrasion 0-10

0--Total failure of fabric specimen. Fibers are torn apart

5--Fabric specimen is starting to tear. Fabric is noticeably thinner

10--Original unabraded fabric specimen

                                      TABLE VI    __________________________________________________________________________    SPECIMENS           UNTREATED FABRIC                      ENCAPSULATED FABRIC                                   COMMENTS    __________________________________________________________________________    Hot Coral           5          7            Untreated sample is    Tactel 1,000 cyc. 1,000 cyc.   starting to tear, and                                   enveloped sample was                                   still intact.    Deva Blue           4          7            Visible rips in    Tactel 1,000 cyc. 1,000 cyc.   untreated sample.                                   Enveloped sample                                   fibers were frayed.    __________________________________________________________________________

Example 28 Breathability Testing

This test procedure followed the Modified ASTM E96-8 test. As shown bythe results of this testing in the following Table, the fiber envelopedfabrics of this invention were found to have high breathability. Thisbreathability was in excess of that needed to remove the average valueof several thousand grams of perspiration generated daily by the humanbody. The results for the fiber enveloped fabrics of this invention weregenerally superior to the corresponding results measured under the sameconditions for prior art treated fabrics, such as the Gore-Tex® brandfabric.

Breathability of a fabric sample was determined by accurately weighingthe amount of water passing through such fabric sample under carefullycontrolled temperature and relative humidity conditions in anenvironmental chamber. The water weight loss from a cup whose mouth issealed with a fabric sample was expressed as grams of water vapor persquare meter of fabric per 24 hour day.

In an attempt to more realistically simulate what is actually occurringinside the apparel during exercise, a specially designed test wasperformed to measure outward water vapor transport (MVTR) in a "Bellows"effect. The test simulates the high volumes of moisture and air that mixwithin a garment that pass outward through it as air is drawn inresultant from activity. The enveloped fabrics of this invention werefound to provide increased performance at a higher activity, or airexchange level than is achievable with corresponding untreated fabrics.

The "Bellows" MVTR breathability test was run inside of a controlledtemperature/humidity chamber similar to the foregoing cup test. However,instead of a standard cup, each fabric sample was sealed over the opentop of a special cup which was provided with an air inlet aperture inits bottom, thereby allowing air to be bubbled up through the sealedcontainer at a controlled rate. A check valve at the air inlet operationprevents backup or loss of water from the container. The air bubblespassed upwardly through the water and out through the fabric samplemounted sealingly across the cup top along with the water vapor. TableVII illustrates some representation results obtained.

                  TABLE VII    ______________________________________    Moisture Vapor Transport (MVTR)    FABRIC                 MVTR.sup.(1)    ______________________________________    Made by a Method of the Invention                           13,600    Enveloped fiber fabric, Hot Coral Tactel ®    Commercial Products    10,711    Gore-Tex\3-Ply Fabric    ______________________________________     Table Footnote:     .sup.(1) MVTR here references moisture vapor transport through a fabric     sample as measured by "Bellows" test with air delivered to the bubbler at     2 to 4 psi air pressure, in an Environmental Chamber at 100 to     102°0 F. and 38-42% relative humidity. MVTR is expressed as grams     of water per square meter of surface per 24 hour day.

Example 29 Water Repellency: Spray Testing

Water repellency spray testing is carried out according to AATCC TestMethod 22-1974. The results of such testing show that the fiberenveloped Tactel®-type fabrics of the invention show excellent initialspray ratings initially, as do the original untreated fabrics which havebeen treated with water repellent chemicals such as fluorochemicals.Specifically, as the results shown below demonstrate, after ten machinewashes, the treated side of a fiber enveloped fabric of the inventionwas found to remain highly water repellent, while, on the reverse sidethereof, the original water repellency rating was found to have fallensignificantly. The water repellency spray rating on the untreated fabricfell even more drastically. Excellent "hand" was retained after thetest. It is believed that pretreatment with a fluorochemical having goodwater repellent properties can augment and even synergistically coactwith the silicone resin used to produce fiber enveloped fabrics of thisinvention to produce superior spray ratings in such a fiber. The resultsare shown in Table VIII.

This test method is believed to be applicable to any textile fabric,whether or not it has been given a water resistant or water-repellentfinish. The purpose of the test is to measure the resistance of fabricsto wetting by measuring the water-repellent efficiency of finishesapplied to fabrics, particularly to plain woven fabrics. The portabilityand simplicity of the instrument, and the shortness and simplicity ofthe test procedure, make this method of test especially suitable formill production control work. This test method is not intended, however,for use in predicting the probable rain penetration resistance offabrics, since it does not measure penetration of water through thefabric.

The results obtained with this test method are believed to dependprimarily on the resistance to wetting, or the water repellency, of thefibers and yarns comprising a fabric, and not upon the construction ofthe fabric. This test involves spraying water against the taut surfaceof a test fabric specimen under controlled conditions which produce awetted pattern whose size depends on the relative water repellency ofthe fabric. Evaluation is accomplished by comparing the wetted patternwith pictures on a standard chart. The methods and apparatus andmaterials employed for this test were an AATCC Spray Tester, a beaker,distilled water, and the specimen fabrics.

The procedure followed for this test was as follows: a test specimen,which had been conditioned as procedurally directed, was fastenedsecurely in a 15.2 cm (6") metal hoop so that it presented a smoothwrinklefree surface. The hoop was then placed on the stand of the testerso that the fabric was uppermost in such a position that the center ofthe spray pattern coincided with the center of the hoop. In the case oftwills, gabardines, piques or fabrics of similar ribbed construction,the hoop was placed on the stand in such a way that the ribs werediagonal to the flow of water running off the fabric specimen. 250milliliters (ml) of distilled water at 27° C.±1° C. (80° F.±2° F.) waspoured into the funnel of the tester and allowed to spray onto the testspecimen, which took approximately 25 to 30 seconds. Upon completion ofthe spraying period, the hoop was taken by one edge and the oppositeedge tapped smartly once against a solid object, with the fabric facingthe object. The hoop was then rotated 180 degrees and then tapped oncemore on the location previously held.

The procedure and methods and apparatus of this test were slightlymodified from the specifications, as follows:

1. The spray nozzle holes were slightly larger than specified, but theflow rate of the nozzle was 250 ml/30 sec., as required.

2. The number of taps of the hoop was two instead of one.

For each wash test, a fabric sample was washed using a warm wash/coldrinse cycle with one cup of Tide® detergent and dried at a hot/dry cyclein a dryer, unless otherwise indicated. The test results were evaluatedby comparing the wet or spotted pattern on the fabric sample aftertapping the hoop with the standard rating chart. Results producedsurface wetting, with no water completely soaking through the testfabric sample. The numbers were ratings based upon the standard chart.Such values are thus subjective deductions by an experiencedexperimenter.

                                      TABLE VIII    __________________________________________________________________________    Spray Test Results    ORIGINAL    FABRIC          ENVELOPED FIBER FABRIC OF THE INVENTION    Tactel ®          Initial         After 5 Washes                                   After 10 Washes    Color    After 4                 Enveloped                      Reverse                          Enveloped                               Reverse                                   Enveloped                                        Reverse    & Number          Initial             Washes                 Side Side                          Side Side                                   Side Side    __________________________________________________________________________    Deva Blue          100             10  90   100 90   70  80   50    9-420-6-1    Hot Coral          100             30  90   100 70   55  70   30    9-420-6-2    Gold Tactel          100             100 90   90  90   90  90   90    8-100-1    __________________________________________________________________________

Example 30 Moisture Penetration Test

The results shown in the Table below demonstrate that all of the fiberenveloped fabrics of this invention test were significantly better thanthe original untreated fabrics with regard to resisting the penetrationof water under the test conditions used after the test, the "hand" ofthe tested fabric samples remained excellent.

The purpose of this test was to evaluate how well a fabric stands up towetness under continuous pressure, such as kneeling on the ground, orsitting in a wet chairlift, for a period of 30 minutes. This testinvolves placing both a fabric sample and a standard blotter sample ontop of a water container which contains 700 ml of tap water. The fabricsample and the blotter sample are each then subjected to a continuouspressure of 87 lbs. distributed evenly over 100 square inches of surfacearea for a period of 30 minutes. After this time, a visual inspection ofthe fabric is made for any water penetration, and the paper blotter isweighed to detect water gain or penetration.

The methods and apparatus employed for each such test was one 20 inchdiameter aluminum pan, one 87 lbs. weight distributed evenly over 100square inches of fabric, one paper blotter, 700 ml water, miscellaneousfabric scraps for cushioning and the test fabric sample pieces.

Paper blotter dry weight: 4.7 gm

Total weight applied to fabric: 87 lbs.

Pressure evenly distributed over surface area of: 100 sq. in.

Pressure: 0.87 lbs./sq.in

The procedure observed for this test was as follows:

1. 700 ml tap water was placed in the round pan.

2. The fabric sample was placed with one side facing the water.

3. One piece of dry blotter paper was placed over the fabric to coverthe pan.

4. Scrap fabric was placed over the blotter paper to cushion the weight.

5. The 87 lb. weight was distributed evenly over the 100-square-incharea.

6. This assembly was left undisturbed for 30 minutes.

7. After this time period, the visual results were recorded.

                                      TABLE IX    __________________________________________________________________________    Fiber Enveloped Fabric of the Invention             ENVELOPED SIDE                       NON-ENVELOPED    FABRIC SAMPLE             OF FABRIC SIDE OF FABRIC                                  CONTROL    AND THICKNESS             FACING WATER                       FACING WATER                                  FABRIC    __________________________________________________________________________    Deva Blue             No water penetration                       No water penetration                                  Failure - total    Tactel ®             through the fabric. No                       through the fabric. No                                  saturation of fabric    0.009 microns             visible water spots.                       visible water spots. Paper                                  and blotter.             Paper weight = 4.7 gm                       weight = 4.7 gm Water             Water gain = 0.0 gm                       gain = 0.0 gm    __________________________________________________________________________

Example 31 Rain Test

In this testing, the rain test procedure of AATCC Method 35-1985 wasfollowed.

The rain test results obtained demonstrate the clear superiority of thefiber enveloped fabric of the present invention as compared to theoriginal untreated fabric. The data in the Table below shows that fiberenveloped fabrics pass this test by allowing virtually no water to passtherethrough. This result is comparable to the results obtained withhigher cost so-called breathable waterproof fabrics currentlycommercially available in the market. In contrast, the original,untreated fabrics fail to pass this test because they demonstratecomplete saturation. The fiber enveloped fabric samples retain excellent"hand" after the test.

The purpose and scope of this ASTM test is to evaluate resistance of afiber enveloped fabric to water under simulated storm conditions. Thetest specifies that a test fabric is stormproof if less than one gram ofwater is absorbed by blotter paper with a shower head pressure of 3 feetexerted for 5 minutes. This test method is applicable to any textilefabric, whether or not it has a water repellent finish. It measures theresistance of a fabric to the penetration of water by impact, and thuscan be used to predict the probably rain penetration resistance of afabric. The results obtained with this method of test depend on thewater repellency of the fibers and yarns in the fabric tested, and onthe construction of the fabric.

This test involves a test specimen backed by a pre-weighed standardblotter. The assembly is sprayed with water for 5 minutes undercontrolled conditions. The blotter then is separated and weighted todetermine the amount of water, if any, which has leaked through thespecimen fabric during the test and has been absorbed by the blotter.

The methods and apparatus and materials employed in each test were amodified rain tester, blotter paper, water at 80° F.±2° F., a laboratorybalance, 8"×8" fabric specimens which had been pre-conditioned in anatmosphere of 65% (±2%) relative humidity and 70° F. (±2° F.) for fourhours before testing, and tape.

The procedure followed for this test was as follows:

1. A 6"×6" paper blotter was weighted to the nearest 0.1 gm and placedbehind the test specimen.

2. The test fabric with the paper blotter in registration therewith wastaped on the specimen holder.

3. A tube in the rain tester was filled with water up to the 3 footlevel. It was confirmed that water was flowing out of the overflow tubewhich maintains the 3 foot column of water.

4. The water spray distance from the tip of the nozzle to the specimenholder was measured and adjusted to 12 inches.

5. The specimen holder was left in place and the rain tester was turnedon for five minutes.

6. After the test period, the paper blotter was removed and reweighed tothe nearest 0.1 gm.

The results of the test selected fabric samples are shown in Table X.

                  TABLE X    ______________________________________    Rain Test: Grams of Water Penetrating the Fabric                             AFTER 5   AFTER 10                 ORIGINAL NOT                             MACHINE   MACHINE    FABRIC SAMPLE                 WASHED      WASHES    WASHES    ______________________________________    Hot Coral Tactel°                 0           0         0    Deva Blue Tactel°                 0           0         0    Prior Art Treated Fabrics    Ultrex°                 0           --        0.1    Gore-Tex°                 0           0         --    ______________________________________

Original Fabrics--Water Repellant Chemicals Only. No Encapsulation

Hot Coral Tactel/Failed-saturated

Deva Blue Tactel/Failed-saturated

It should be understood, of course, that the foregoing relates only topreferred embodiments of the present invention and that numerousmodifications or alterations may be made therein without departing fromthe spirit and the scope of the invention as set forth in the appendedclaims.

What is claimed is:
 1. A method of controlled placement of a curable,shear-thinnable, polymer composition into a porous web, having a threedimensional structure of a plurality of structural elements withinterstitial spaces therebetween comprising:applying tension to theporous web; applying a polymer composition onto one surface of thetensioned porous web; and shear thinning the polymer compositionsufficiently to reduce its viscosity and selectively place the viscosityreduced polymer composition into the tensioned web to encapsulate atleast some of the structural elements, leaving most of the interstitialspaces open.
 2. The method of controlled placement according to claim 1further comprising:distorting the porous web at the location of theshear thinning to facilitate entrance of the polymer composition intothe web.
 3. The method of controlled placement according to claim 2wherein the distorting comprises stretching.
 4. The method of controlledplacement according to claim 2 wherein the distorting is by passage ofthe web against a rotating roller.
 5. The method of controlled placementaccording to claim 1 wherein the web is moved in one direction against aroller which rotates in the opposite direction, and the polymercomposition is applied between the roller and the moving web.
 6. Themethod of controlled placement according to claim 1 further comprisingpassing the treated web through a pair of nip rolls under longitudinaltension and allowing the tension to be released upon exiting the niprolls to permit the structural elements of the porous web to separatefrom each other.
 7. A method of controlled placement of a curable,shear-thinnable, polymer composition into a porous web, having a threedimensional structure of a plurality of structural elements withinterstitial spaces therebetween, comprising:applying a polymercomposition onto one surface of the porous web; applying tension to saidporous web; forcing at least one blade against said one surface of theporous web; moving the web relative to said blade; and controlling thetension of said web and the force of said blade to shear thin thepolymer composition to reduce its viscosity and to selectively place itinto the tensioned web to encapsulate at least some of the structuralelements, leaving most of the interstitial spaces open.
 8. The method ofcontrolled placement according to claim 7 further comprising:distortingthe porous web at the location of the shear thinning to facilitateentrance of the polymer composition into the web.
 9. The method ofcontrolled placement according to claim 8 wherein the distortingcomprises stretching.
 10. The method of controlled placement accordingto claim 9 wherein the stretching is by passage of the web against arotating roller.
 11. The method of controlled placement according toclaim 9 wherein the distorting by stretching is by passage of the webbetween a first roller and a second roller.
 12. The method of controlledplacement according to claim 11 wherein the first and second rollers arerotating in the same direction.
 13. The method of controlled placementaccording to claim 11 wherein the first and second rollers rotateopposite to movement of the web past the localized area.
 14. The methodof controlled placement according to claim 11 wherein the distorting bystretching is between first and second rollers at least one of whichexhibits a gravure surface.
 15. The method of controlled placementaccording to claim 11 wherein the distorting by stretching is betweenfirst and second rollers at least one of which exhibits a smoothsurface.
 16. The method of controlled placement according to claim 2wherein the distorting is by passage of the tensioned web against atleast one blade.
 17. The method of controlled placement according toclaims 1 or 7 further comprising:extracting polymer composition from thesurface of the web and from within the web.
 18. The method of controlledplacement according to claim 1 wherein the shear thinning and placingcomprises:first pressuring in a pressured application stage thatdelivers the polymer composition into the porous web under pressure;second pressuring in a pressured second stage that extracts some of thepolymer composition that is in and upon the porous web and reintroducesthe extracted polymer composition into the web under pressure.
 19. Themethod of controlled placement according to claim 18 wherein the firstpressuring comprises:rolling the polymer composition into the porous webunder pressure; and wherein the second pressuring comprises: extractingexcess polymer composition with at least one blade.
 20. The method ofcontrolled placement according to claim 19wherein the rolling is betweentwo rollers rotating in the same direction thereby stretching the webbetween the rollers simultaneously so that the polymer composition isrolled onto and into the porous web under pressure.
 21. A method ofcontrolled placement according to claim 1 wherein the polymercomposition is selectively placed in an internal layer within said web.22. A method of controlled placement in accordance with claim 7 whereinthe shear thinning and placing is controlled to also selectively placethe polymer composition in an internal layer within said web.
 23. Amethod of controlling the placement of a polymer composition into aporous substrate having a matrix of open cells therein comprising thesteps of:applying tension longitudinally to said substrate; applying acurable, shear thinnable polymer composition having a viscositysufficient to line the walls of said cells to at least one surface ofsaid substrate; moving against said surface of the tensioned substrate auniformly applied localized shear force to selectively distribute saidcomposition within said substrate, at least partially individuallylining cell walls of at least some of said cells with said composition,and leaving most of said cells open.
 24. A method of controlledplacement according to claim 1 wherein said shear thinning includesforcing one or more blades against the surface of the tensioned web;saidblades having a leading edge, a trailing edge, and a bottom surface. 25.A method of controlled placement according to claim 24 includingcontrolling the force of each blade against said tensioned web.
 26. Amethod of controlled placement according to claim 24 further comprisingmoving the tensioned web relative to said blade and controlling thetension of the web as it passes each blade.
 27. A method of controlledplacement according to claim 24 comprising controlling the temperatureof each blade.
 28. A method of controlled placement according to claim26 comprising controlling the entrance angle of the web and the exitangle of the web from each blade.
 29. A method of controlled placementaccording to claim 24 comprising controlling the resonance of eachblade.
 30. A method of controlled placement according to claim 24further comprising the step of applying a transverse force to said webafter shear thinning.
 31. A method according to claim 23 wherein thepolymer composition is also selectively placed in an internal layerwithin said web.
 32. The method of claim 31 wherein said polymercomposition has a viscosity greater than about 5,000 and less than about2,000,000 centipoise.
 33. The method of claims 1 or 23 furthercomprising the step of curing the polymer composition in said substrate.34. The method of claim 33 wherein said curing is accomplished by heator radiation.
 35. The method of claims 1 or 23 wherein the substrate issubstantially uniformly impregnated with a fluorochemical prior toapplying the polymer composition.
 36. The method of claim 23 whereinsaid porous substrate is selected from the group consisting of naturaland synthetic leathers, porous paper, open celled plastic, and opencelled sheet structure.
 37. The method of claim 23 wherein saidsubstrate comprises a layer of an open celled, porous, flexible materialand a layer of a non-porous flexible material.
 38. The method of claim35 wherein said fluorochemical impregnating is carried out by the stepscomprising:(a) substantially completely saturating said substrate with adispersion of a fluorochemical containing composition in a carrierliquid; (b) compressing the saturated substrate to remove therefromexcess portions of said dispersion; and (c) heating said substrate toevaporate said carrier liquid therefrom.
 39. The method of claim 38wherein the fluorochemical impregnated web has a weight increase in therange of about 0.01 to about 5 weight percent of the weight of theuntreated web.
 40. The method of claim 39 wherein the polymercomposition impregnated web has a weight increase in the range of about5 to about 200 weight percent compared to the weight of the untreatedweb.
 41. A method of controlled placement as set forth in claim 1wherein the polymer composition includes an additive and at least someof said additive is selectively placed on the surface of theencapsulated structural elements.
 42. A method of controlled placementas set forth in claim 21 wherein the polymer composition includes anadditive and at least some of said additive is selectively placed on oneor both surfaces of the internal layer.
 43. A method of controlledplacement as set forth in claim 1 wherein said polymer compositionincludes an additive and at least some of said additive is selectivelyplaced on one or both surfaces of said web.
 44. The method of claim 1wherein said polymer composition is selectively placed to encapsulatemost of the structural elements of said web.
 45. The method of claim 1wherein said polymer composition is selectively placed to encapsulatesubstantially all of the structural elements of said web.
 46. The methodof claim 1 wherein said shear thinning means leaves substantially all ofthe interstitial spaces open.
 47. The method of claim 46 wherein saidpolymer composition is selectively placed to encapsulate most of thestructural elements of said web.
 48. The method of claim 46 wherein saidpolymer composition is selectively placed to encapsulate substantiallyall of the structural elements of said web.
 49. The method of claim 1wherein:said polymer composition is selectively placed to form asubstantially continuous region extending through the web, said regionof polymer composition filling the interstitial spaces and adheringadjacent structural elements; said polymer composition is selectivelyplaced to encapsulate at least some of the structural elements above andbelow said region; and most of the interstitial spaces between saidencapsulated structural elements above and below said region are open.50. A method of controlled placement as set forth in claim 49 whereinthe polymer composition includes an additive and at least some of saidadditive is placed on the surface of the encapsulated structuralelements and at least some of said additive is placed on one or bothsurfaces of the polymer region that faces the top and bottom surfaces ofthe web.
 51. The method of claim 24 wherein said shear thinning includesforcing two or more blades, spaced apart from one another, against thesurface of the tensioned web.
 52. The method of claim 51 includingcontrolling the force of each blade against said tensioned web.
 53. Themethod of claim 51 further comprising moving the tensioned web relativeto said blade and controlling the tension of the web as it passes eachblade.
 54. The method of claim 51 comprising controlling the temperatureof each blade.
 55. The method of claim 53 comprising controlling theentrance angle of the web and the exit angle of the web from each blade.56. The method of claim 51 comprising controlling the resonance of eachblade.
 57. The method of claim 51 further comprising the step ofapplying a transverse force to said web after shear thinning andplacing.
 58. The method of claim 1 wherein said polymer composition hasa viscosity greater than about 5,000 and less than about 2,000,000centipoise.
 59. The method of claims 32 or 58 wherein said polymercomposition has a viscosity greater than about 100,000 centipoise. 60.The method of claims 32 or 58 wherein said polymer composition has aviscosity greater than about 200,000 centipoise.
 61. The method ofclaims 1 or 31 wherein said polymer composition has predeterminedrheological characteristics.
 62. The method of claim 40 wherein thepolymer composition impregnated web has a weight increase in the rangeof about 10 to about 100 weight percent compared to the weight of theuntreated web.
 63. The method of claim 24 further comprising extractingpolymer composition from the surface of the web and from within the web,and reintroducing it into the web.
 64. The method of claim 24 whereinsaid leading and trailing edges are defined by adjacent surfaces of atleast a root mean square of
 8. 65. The method of claim 35 wherein saidfluorochemical impregnated substrate is both longitudinally andlaterally tensioned.
 66. The method of claim 1 further comprisingseparating the structural elements after said shear thinning step. 67.The method of claim 33, including controlling the release of tension ofsaid web to cause the structural elements to separate prior to cure. 68.The method of claim 33, wherein said web is under substantially notension during curing.
 69. The method of claim 33, including means forholding said web under transverse tension during curing.
 70. The methodof claims 7 or 24, including means for separating the structuralelements of the web.
 71. A method of controlled placement of a curable,shear-thinnable polymer composition into a porous web as set forth inclaim 1, whereby the polymer composition is essentially free of solvent.72. A method of controlled placement of a curable, shear-thinnablepolymer composition into a porous web as set forth in claim 7, wherebythe polymer composition is essentially free of solvent.
 73. A method ofcontrolled placement of a curable, shear-thinnable polymer compositioninto a porous substrate as set forth in claim 23, whereby the polymercomposition is essentially free of solvent.